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	<updated>2026-04-05T22:57:25Z</updated>
	<subtitle>User contributions</subtitle>
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	<entry>
		<id>https://michaelnielsen.org/polymath/index.php?title=Linear_norm_grant_acknowledgments&amp;diff=11021</id>
		<title>Linear norm grant acknowledgments</title>
		<link rel="alternate" type="text/html" href="https://michaelnielsen.org/polymath/index.php?title=Linear_norm_grant_acknowledgments&amp;diff=11021"/>
		<updated>2019-03-10T06:25:29Z</updated>

		<summary type="html">&lt;p&gt;Khare: /* Grant information */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;Participants should be arranged in alphabetical order of surname.&lt;br /&gt;
&lt;br /&gt;
== Participants and contact information ==&lt;br /&gt;
&lt;br /&gt;
Caution: this list may be incomplete.  Participants who have made significant contributions to the project (on par with a co-author on a traditional mathematical research paper) should add themselves to this list, or email tao@math.ucla.edu if they are unable to do so directly.  Participants who have made auxiliary contributions to the project (on par with those mentioned in an Acknowledgments section in a traditional paper) should add themselves instead to the list at the bottom of the page. &lt;br /&gt;
&lt;br /&gt;
* Tobias Fritz, MPI MIS, [http://personal-homepages.mis.mpg.de/fritz/]&lt;br /&gt;
* Siddhartha Gadgil, Indian Institute of Science, Bangalore [http://math.iisc.ac.in/~gadgil/]&lt;br /&gt;
* Apoorva Khare, Indian Institute of Science, Bangalore, and the Analysis and Probability Research Group, Bangalore [http://www.math.iisc.ac.in/~khare/]&lt;br /&gt;
* Pace Nielsen, BYU, [https://math.byu.edu/~pace/]&lt;br /&gt;
* Lior Silberman, UBC, [https://www.math.ubc.ca/~lior/]&lt;br /&gt;
* Terence Tao, UCLA, [http://www.math.ucla.edu/~tao]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== Grant information ===&lt;br /&gt;
&lt;br /&gt;
* Apoorva Khare was supported by Ramanujan Fellowship SB/S2/RJN-121/2017 and MATRICS grant MTR/2017/000295 from SERB (DST, Govt.~of India), by grant F.510/25/CAS-II/2018(SAP-I) from UGC (DST, Govt.~of India), and by a Young Investigator Award from the Infosys Foundation.&lt;br /&gt;
* Pace Nielsen was supported by  NSA grant H98230-16-1-0048.&lt;br /&gt;
* Lior Silberman was supported by an NSERC Discovery grant. &lt;br /&gt;
* Terence Tao was supported by a Simons Investigator grant, the James and Carol Collins Chair, the Mathematical Analysis &amp;amp; Application Research Fund Endowment, and by NSF grant DMS-1266164.&lt;br /&gt;
&lt;br /&gt;
=== Other acknowledgments ===&lt;br /&gt;
&lt;br /&gt;
Other contributors to the project include Sean Eberhard, Tobias Hartnick, Chris Jerdonek, Antonio Machiavelo, Andy Putman, Will Sawin, Alexander Shamov, and David Speyer.&lt;br /&gt;
&lt;br /&gt;
Thanks to Michael Nielsen for hosting the polymath wiki for this project.&lt;/div&gt;</summary>
		<author><name>Khare</name></author>
	</entry>
	<entry>
		<id>https://michaelnielsen.org/polymath/index.php?title=Linear_norm&amp;diff=10949</id>
		<title>Linear norm</title>
		<link rel="alternate" type="text/html" href="https://michaelnielsen.org/polymath/index.php?title=Linear_norm&amp;diff=10949"/>
		<updated>2018-11-27T18:12:16Z</updated>

		<summary type="html">&lt;p&gt;Khare: /* Writeup */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;This is the wiki page for understanding &#039;&#039;seminorms of linear growth&#039;&#039; on a group &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; (such as the free group on two generators).  These are functions &amp;lt;math&amp;gt;\| \|: G \to [0,+\infty)&amp;lt;/math&amp;gt; that obey the triangle inequality&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;\|xy\| \leq \|x\| + \|y\| \quad (1)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
and the linear growth condition&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \|x^n \| = |n| \|x\| \quad (2) &amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
for all &amp;lt;math&amp;gt;x,y \in G&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;n \in {\bf Z}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
We use the usual group theory notations &amp;lt;math&amp;gt;x^y := yxy^{-1}&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;[x,y] := xyx^{-1}y^{-1}&amp;lt;/math&amp;gt;.&lt;br /&gt;
  &lt;br /&gt;
== Threads ==&lt;br /&gt;
&lt;br /&gt;
* [https://terrytao.wordpress.com/2017/12/16/bi-invariant-metrics-of-linear-growth-on-the-free-group/ Bi-invariant metrics of linear growth on the free group], Dec 16 2017.&lt;br /&gt;
* [https://terrytao.wordpress.com/2017/12/19/bi-invariant-metrics-of-linear-growth-on-the-free-group-ii/ Bi-invariant metrics of linear growth on the free group, II], Dec 19 2017.&lt;br /&gt;
* [https://terrytao.wordpress.com/2017/12/21/metrics-of-linear-growth-the-solution/ Metrics of linear growth – the solution], Dec 21 2017.&lt;br /&gt;
* [https://terrytao.wordpress.com/2018/01/11/homogeneous-length-functions-on-groups/ Homogeneous length functions on groups], Jan 11 2018.&lt;br /&gt;
&lt;br /&gt;
== Key lemmas ==&lt;br /&gt;
&lt;br /&gt;
Henceforth we assume we have a seminorm &amp;lt;math&amp;gt;\| \|&amp;lt;/math&amp;gt; of linear growth.  The letters &amp;lt;math&amp;gt;s,t,x,y,z,w&amp;lt;/math&amp;gt; are always understood to be in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;i,j,n,m&amp;lt;/math&amp;gt; are always understood to be integers.&lt;br /&gt;
&lt;br /&gt;
From (2) we of course have&lt;br /&gt;
:&amp;lt;math&amp;gt; \|x^{-1} \| = \| x\| \quad (3)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Lemma 1&#039;&#039;&#039;. If &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; is conjugate to &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\|x\| = \|y\|&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  By hypothesis, &amp;lt;math&amp;gt;x = zyz^{-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;z&amp;lt;/math&amp;gt;, thus &amp;lt;math&amp;gt;x^n = z y^n z^{-1}&amp;lt;/math&amp;gt;, hence by the triangle inequality&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; n \|x\| = \|x^n \| \leq \|z\| + n \|y\| + \|z^{-1} \|&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
for any &amp;lt;math&amp;gt;n \geq 1&amp;lt;/math&amp;gt;.  Dividing by &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; and taking limits we conclude that &amp;lt;math&amp;gt;\|x\| \leq \|y\|&amp;lt;/math&amp;gt;.  Similarly &amp;lt;math&amp;gt;\|y\| \leq \|x\|&amp;lt;/math&amp;gt;, giving the claim. &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
An equivalent form of the lemma is that&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \|xy\| = \|yx\| \quad (4).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
We can generalise Lemma 1:&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Lemma 2&#039;&#039;&#039;.  If &amp;lt;math&amp;gt;x^i&amp;lt;/math&amp;gt; is conjugate to &amp;lt;math&amp;gt;wy&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;x^j&amp;lt;/math&amp;gt; is conjugate to &amp;lt;math&amp;gt;zw^{-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt; \|x\| \leq \frac{1}{|i+j|} ( \|w\| + \|z\| )&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  By hypothesis, &amp;lt;math&amp;gt;x^i = s wy s^{-1}&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;x^j = t zw^{-1} t^{-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;s,t&amp;lt;/math&amp;gt;.  For any natural number &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt;, we then have&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; x^{in} x^{jn} = s wy \dots wy s^{-1} t zw^{-1} \dots zw^{-1} t^{-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where the terms &amp;lt;math&amp;gt;wy, zw&amp;lt;/math&amp;gt; are each repeated &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; times.  By Lemma 1, conjugation by &amp;lt;math&amp;gt;w&amp;lt;/math&amp;gt; does not change the norm.  From many applications of this and the triangle inequality, we conclude that&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; |i+j| n \|x\| = \| x^{in} x^{jn} \| \leq \|s\| + n \|y\| + \|s^{-1} t\| + n \|z\| + \|t^{-1}\|.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Dividing by &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; and sending &amp;lt;math&amp;gt;n \to \infty&amp;lt;/math&amp;gt;, we obtain the claim.  &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
== Corollaries ==&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Corollary 0&#039;&#039;&#039;.  The eight commutators &amp;lt;math&amp;gt;[x^{\pm 1}, y^{\pm 1}], [y^{\pm 1}, x^{\pm 1}]&amp;lt;/math&amp;gt; all have the same norm.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  Each of these commutators is conjugate to either &amp;lt;math&amp;gt;[x,y]&amp;lt;/math&amp;gt; or its inverse. &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Corollary 1&#039;&#039;&#039;.  The function &amp;lt;math&amp;gt;n \mapsto \|x^n y\|&amp;lt;/math&amp;gt; is convex in &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  &amp;lt;math&amp;gt;x^n y&amp;lt;/math&amp;gt; is conjugate to &amp;lt;math&amp;gt;x (x^{n-1} y)&amp;lt;/math&amp;gt; and to &amp;lt;math&amp;gt;(x^{n+1} y) x^{-1}&amp;lt;/math&amp;gt;, hence by Lemma 2&lt;br /&gt;
:&amp;lt;math&amp;gt;\| x^n y \| \leq \frac{1}{2} (\| x^{n-1} y \| + \| x^{n+1} y \|),&amp;lt;/math&amp;gt;&lt;br /&gt;
giving the claim.  &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Corollary 2&#039;&#039;&#039;. For any &amp;lt;math&amp;gt;k \geq 1&amp;lt;/math&amp;gt;, one has&lt;br /&gt;
:&amp;lt;math&amp;gt;\| [x,y] \| \leq \frac{1}{2k+2} (\| [x^{-1},y^{-1}]^k x^{-1} \| + \| [x,y]^k x \|).&amp;lt;/math&amp;gt;&lt;br /&gt;
Thus for instance&lt;br /&gt;
:&amp;lt;math&amp;gt;\| [x,y] \| \leq \frac{1}{4} (\| [x^{-1},y^{-1}] x^{-1} \| + \| [x,y] x \|).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  &amp;lt;math&amp;gt;[x,y]^{k+1}&amp;lt;/math&amp;gt; is conjugate both to &amp;lt;math&amp;gt;x(y[x^{-1},y^{-1}]^k x^{-1}y^{-1})&amp;lt;/math&amp;gt; and to &amp;lt;math&amp;gt;(y^{-1} [x,y]^k xy)x^{-1}&amp;lt;/math&amp;gt;, hence by Lemma 2&lt;br /&gt;
:&amp;lt;math&amp;gt; \| [x,y] \| \leq \frac{1}{2k+2} ( \| y[x^{-1},y^{-1}]^k x^{-1} \| + \| (y^{-1} [x,y]^k xy)x^{-1}\|)&amp;lt;/math&amp;gt;&lt;br /&gt;
giving the claim by Lemma 1. &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Corollary 3&#039;&#039;&#039;.  One has&lt;br /&gt;
:&amp;lt;math&amp;gt; \|[x,y]^2 x\| \leq \frac{1}{2} ( \| x y^{-1} [x,y] \| +  \| xy [x,y] \| ).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  &amp;lt;math&amp;gt;[x,y]^2 x&amp;lt;/math&amp;gt; is conjugate both to &amp;lt;math&amp;gt;y (x^{-1} y^{-1} [x,y] x^2)&amp;lt;/math&amp;gt; and to &amp;lt;math&amp;gt;(x[x,y]xyx^{-1}) y^{-1}&amp;lt;/math&amp;gt;, hence by Lemma 2&lt;br /&gt;
:&amp;lt;math&amp;gt; \displaystyle \|[x,y]^2 x\| \leq \frac{1}{2} ( \|x^{-1} y^{-1} [x,y] x^2\| + \|x[x,y]xyx^{-1}\|)&amp;lt;/math&amp;gt;&lt;br /&gt;
giving the claim by Lemma 1. &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Corollary 4&#039;&#039;&#039;.  One has&lt;br /&gt;
:&amp;lt;math&amp;gt;\| [x,y] x\| \leq \frac{1}{4} ( \| x^2 y [x,y] \| + \| xy^{-1} x [x,y] \| ).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;. &amp;lt;math&amp;gt;([x,y] x)^2&amp;lt;/math&amp;gt; is conjugate both to &amp;lt;math&amp;gt;y^{-1} (x [x,y] x^2 y x^{-1})&amp;lt;/math&amp;gt; and to &amp;lt;math&amp;gt;(x^{-1} y^{-1} x [x,y] x^2) y&amp;lt;/math&amp;gt;, hence Lemma 2&lt;br /&gt;
:&amp;lt;math&amp;gt;\| [x,y] x\| \leq \frac{1}{4} ( \| x [x,y] x^2 y x^{-1} \| + \| x^{-1} y^{-1} x [x,y] x^2 \| ),&amp;lt;/math&amp;gt;&lt;br /&gt;
giving the claim by Lemma 1. &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Corollary 5&#039;&#039;&#039;.  One has&lt;br /&gt;
:&amp;lt;math&amp;gt; \|[x,y] x\| \leq \|x\| + \frac{1}{2} \| [x^2, y] \|&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;. &amp;lt;math&amp;gt;[x,y]x&amp;lt;/math&amp;gt; is conjugate to both &amp;lt;math&amp;gt;x [x^{-2},y^{-1}]&amp;lt;/math&amp;gt; and to &amp;lt;math&amp;gt;(y^{-1} x^2 y) x^{-1}&amp;lt;/math&amp;gt;, hence by Lemma 2&lt;br /&gt;
:&amp;lt;math&amp;gt;\| [x,y] x\| \leq \frac{1}{2} ( \| [x^{-2}, y^{-1}] \| + \| y^{-1} x^2 y \| ),&amp;lt;/math&amp;gt;&lt;br /&gt;
giving the claim by Lemma 1 and Corollary 0. &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Corollary 6&#039;&#039;&#039;.  One has&lt;br /&gt;
:&amp;lt;math&amp;gt; \| [x,y]\| \leq \frac{1}{4} ( \| x\| + \| [x^2,y] \| + \| [x,y] x\| ) &amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  From Lemma 2 we have&lt;br /&gt;
:&amp;lt;math&amp;gt; \| [x,y] \| \leq \frac{1}{4} ( \| x^{-1} [x,y]^2 \| + \| [x,y] x \| ).&amp;lt;/math&amp;gt;&lt;br /&gt;
Since &amp;lt;math&amp;gt;x^{-1} [x,y]^2&amp;lt;/math&amp;gt; is conjugate to &amp;lt;math&amp;gt;(yx^{-1} y^{-1}) (xyx^{-2} y^{-1} x)&amp;lt;/math&amp;gt;, we have&lt;br /&gt;
:&amp;lt;math&amp;gt; \| x^{-1} [x,y]^2 \| \leq \| yx^{-1} y^{-1} \| + \|xyx^{-2} y^{-1} x\|&amp;lt;/math&amp;gt;&lt;br /&gt;
and the claim follows from Lemma 1 and (3).   &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Corollary 7&#039;&#039;&#039;.  For any &amp;lt;math&amp;gt;m,k&amp;lt;/math&amp;gt;, one has&lt;br /&gt;
:&amp;lt;math&amp;gt; \| x^m [x,y]^k \| \leq \frac{1}{2} ( \| x^{m-1} [x,y]^k \| + \|x^{m+1} [x,y]^{k-1} \| )&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  &amp;lt;math&amp;gt;x^m[x,y]^k&amp;lt;/math&amp;gt; is trivially conjugate to &amp;lt;math&amp;gt;x(x^{m-1}[x,y]^k)&amp;lt;/math&amp;gt; and conjugate to &amp;lt;math&amp;gt;(y^{-1}x^m[x,y]^{k-1}xy)x^{-1}&amp;lt;/math&amp;gt;. Hence by Lemma 2,&lt;br /&gt;
:&amp;lt;math&amp;gt;\| x^m[x,y]^k \| \leq \frac{1}{2} ( \| x^{m-1}[x,y]^k \| + \| y^{-1}x^m[x,y]^{k-1}xy \| ) = \frac{1}{2} ( \| x^{m-1}[x,y]^k \| + \| x^{m+1}[x,y]^{k-1} \|),&amp;lt;/math&amp;gt;&lt;br /&gt;
where the final equation is by conjugation invariance (Lemma 1). &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Corollary 8&#039;&#039;&#039;.  One has &amp;lt;math&amp;gt;\|x\| \leq \| [x,y] x \|&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; is equal to both &amp;lt;math&amp;gt; (x^2 y x y^{-1} x^{-2}) (x^2 y x^{-1} y^{-1} x^{-1})&amp;lt;/math&amp;gt; and to &amp;lt;math&amp;gt;(x^2 y x^{-1} y^{-1} x^{-1})^{-1} (x^2 y x^{-1} y^{-1})&amp;lt;/math&amp;gt;, hence by Lemma 2&lt;br /&gt;
:&amp;lt;math&amp;gt; \|x\| \leq \frac{1}{2} ( \| x^2 y x y^{-1} x^{-2} \| + \|x^2 y x^{-1} y^{-1}\| ).&amp;lt;/math&amp;gt;&lt;br /&gt;
By Lemma 1, the RHS is &amp;lt;math&amp;gt;\frac{1}{2} \|x\| + \frac{1}{2} \| [x,y] x \|&amp;lt;/math&amp;gt;, and the claim follows.  &amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Iterations ==&lt;br /&gt;
&lt;br /&gt;
Call a pair of real numbers &amp;lt;math&amp;gt;(\alpha,\beta)&amp;lt;/math&amp;gt; &#039;&#039;&#039;admissible&#039;&#039;&#039; if one has the inequality&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \| [x,y] \| \leq \alpha \|x\| + \beta \|y \|&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
for all &amp;lt;math&amp;gt;x,y&amp;lt;/math&amp;gt;.  Clearly the set of admissible pairs is closed and convex, and if &amp;lt;math&amp;gt;(\alpha,\beta)&amp;lt;/math&amp;gt; is admissible then so is &amp;lt;math&amp;gt;(\alpha&#039;,\beta&#039;)&amp;lt;/math&amp;gt; for any &amp;lt;math&amp;gt;\alpha&#039; \geq \alpha, \beta&#039; \geq \beta&amp;lt;/math&amp;gt;.  From Corollary 0 we also see that the set is symmetric: &amp;lt;math&amp;gt;(\alpha,\beta)&amp;lt;/math&amp;gt; is admissible if and only if &amp;lt;math&amp;gt;(\beta,\alpha)&amp;lt;/math&amp;gt; is.&lt;br /&gt;
&lt;br /&gt;
Writing &amp;lt;math&amp;gt;[x,y] = y^x y^{-1}&amp;lt;/math&amp;gt; we see that &amp;lt;math&amp;gt;(0,2)&amp;lt;/math&amp;gt; is admissible, and similarly so is &amp;lt;math&amp;gt;(0,2)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proposition 1&#039;&#039;&#039;.  If &amp;lt;math&amp;gt;(\alpha,\beta)&amp;lt;/math&amp;gt; is admissible, then so is &amp;lt;math&amp;gt;(\frac{\alpha+1}{2}, \frac{\beta}{4})&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;.  From Corollary 5 and hypothesis one has&lt;br /&gt;
:&amp;lt;math&amp;gt;\| [x,y] x\| \leq \|x\| + \frac{1}{2} ( \alpha \|x^2\| + \beta \|y\| ) = (\alpha+1) \|x\| + \frac{\beta}{2} \|y\|&amp;lt;/math&amp;gt;&lt;br /&gt;
and hence also&lt;br /&gt;
:&amp;lt;math&amp;gt;\| [x^{-1},y^{-1}] x^{-1}\| \leq (\alpha+1) \|x\| + \frac{\beta}{2} \|y\|.&amp;lt;/math&amp;gt;&lt;br /&gt;
From Corollary 2 we thus have&lt;br /&gt;
:&amp;lt;math&amp;gt;\| [x,y]\| \leq \frac{\alpha+1}{2} \|x\| + \frac{\beta}{4} \|y\|.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The map &amp;lt;math&amp;gt;(\alpha,\beta) \mapsto (\frac{\alpha+1}{2}, \frac{\beta}{4})&amp;lt;/math&amp;gt; is a contraction with fixed point &amp;lt;math&amp;gt;(1,0)&amp;lt;/math&amp;gt;.  Thus&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \|[x,y]\| \leq \|x\| \quad (4)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
From symmetry we also see that if &amp;lt;math&amp;gt;(\alpha,\beta)&amp;lt;/math&amp;gt; is admissible, then so is &amp;lt;math&amp;gt;(\frac{\beta+1}{2}, \frac{\alpha}{4})&amp;lt;/math&amp;gt;.  The map &amp;lt;math&amp;gt;(\alpha,\beta) \mapsto (\frac{\beta+1}{2}, \frac{\alpha}{4})&amp;lt;/math&amp;gt; is a contraction with fixed point (4/7,1/7), thus&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \|[x,y]\| \leq \frac{4}{7} \|x\| + \frac{1}{7} \|y\| &amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
== Solution ==&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;Note: this argument only requires Lemma 1, Lemma 2, and Corollary 7 from the preceding sections.&#039;&#039;&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Theorem 1&#039;&#039;&#039; &amp;lt;math&amp;gt;\|[x,y]\| = 0&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Proof&#039;&#039;&#039;  Let &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; be a large natural number.  Write &amp;lt;math&amp;gt;f(m,k) := \| x^m [x,y]^k \|&amp;lt;/math&amp;gt;.  Let &amp;lt;math&amp;gt;X_1,\dots,X_{2n}&amp;lt;/math&amp;gt; be iid random variables, each taking a value of &amp;lt;math&amp;gt;(-1,0)&amp;lt;/math&amp;gt; or &amp;lt;math&amp;gt;(1,-1)&amp;lt;/math&amp;gt; with equal probability &amp;lt;math&amp;gt;1/2&amp;lt;/math&amp;gt;.  From Corollary 7 one has&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;f(m,k) \leq {\bf E} f( (m,k) + X_j)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
for any &amp;lt;math&amp;gt;(m,k), j&amp;lt;/math&amp;gt;, and in particular on iterating&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;f(0, n) \leq {\bf E} f( (0,n) + X_1 + \dots + X_{2n} ).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
By the triangle inequality, we conclude that&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;f(0, n) \leq (\|x\|+\|y\|) {\bf E} | (0,n) + X_1 + \dots + X_{2n} |.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
But the random variable &amp;lt;math&amp;gt;(0,n) + X_1 + \dots + X_{2n}&amp;lt;/math&amp;gt; has mean zero and variance &amp;lt;math&amp;gt;O(n)&amp;lt;/math&amp;gt;, hence by Cauchy-Schwarz&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;f(0, n) \ll n^{1/2} (\|x\|+\|y\|).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
But the left-hand side is &amp;lt;math&amp;gt;n \|[x,y]\|&amp;lt;/math&amp;gt;, so on dividing by &amp;lt;math&amp;gt;n &amp;lt;/math&amp;gt; and taking limits we obtain the claim.&amp;lt;math&amp;gt;\Box&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
As a consequence of this theorem and the triangle inequality, any seminorm on a group will factor through to its abelianisation.&lt;br /&gt;
&lt;br /&gt;
== Writeup ==&lt;br /&gt;
&lt;br /&gt;
* Files for the writeup may be found in [https://www.dropbox.com/sh/wg4y7ptahwq3xo1/AABreDLrXH3hniz1jiFTtvska?dl=0 this directory]. &lt;br /&gt;
* The arXiv preprint may be found [https://arxiv.org/abs/1801.03908 here].&lt;br /&gt;
* The paper has been published in [http://dx.doi.org/10.2140/ant.2018.12.1773 Algebra &amp;amp; Number Theory]].&lt;br /&gt;
&lt;br /&gt;
Here are the [[linear norm grant acknowledgments]].&lt;/div&gt;</summary>
		<author><name>Khare</name></author>
	</entry>
	<entry>
		<id>https://michaelnielsen.org/polymath/index.php?title=Main_Page&amp;diff=10948</id>
		<title>Main Page</title>
		<link rel="alternate" type="text/html" href="https://michaelnielsen.org/polymath/index.php?title=Main_Page&amp;diff=10948"/>
		<updated>2018-11-27T18:10:24Z</updated>

		<summary type="html">&lt;p&gt;Khare: /* Existing polymath projects */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{RightTOC}}&lt;br /&gt;
This is the wiki for &#039;&#039;polymath&#039;&#039; projects - massively collaborative online mathematical projects.  The idea of such projects originated in Tim Gowers&#039; blog post [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?]&lt;br /&gt;
&lt;br /&gt;
Many polymath projects will be proposed, planned, and run at [http://polymathprojects.org/ This Blog].&lt;br /&gt;
&lt;br /&gt;
A Polymath [[logo]] is being trialled.  If you have more suggestions, please add them to the [[logo]] page, or add to the discussion at [[Talk:logo]].&lt;br /&gt;
&lt;br /&gt;
The wiki is currently locked down due to a major influx of spam (July 29, 2013).  Please email mn@michaelnielsen.org if you&#039;d like an account set up, and I&#039;ll do my best to reply quickly. &lt;br /&gt;
&lt;br /&gt;
== Existing polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [[Polymath1]]: New proofs and bounds for the density Hales-Jewett theorem.  Initiated Feb 1, 2009; research results have now been published.&lt;br /&gt;
* [[Definable Banach Spaces|Polymath2]]: Must an “explicitly defined” Banach space contain &amp;lt;math&amp;gt;c_0&amp;lt;/math&amp;gt; or &amp;lt;math&amp;gt;l_p&amp;lt;/math&amp;gt;?  Initiated Feb 17, 2009; attempts to relaunch via wiki, June 9 2010.&lt;br /&gt;
* [[imo 2009 q6|Mini-polymath1]]: Solving Problem 6 of the 2009 International Mathematical Olympiad.  Initiated July 20, 2009; five proofs obtained so far.&lt;br /&gt;
* [[The polynomial Hirsch conjecture|Polymath3]].  The polynomial Hirsch conjecture.  Proposed July 17, 2009; launched, September 30, 2010.  &lt;br /&gt;
* [[finding primes|Polymath4]]: A deterministic way to find primes.  Proposed July 27, 2009; launched Aug 9, 2009.  Research results have now been published.&lt;br /&gt;
* [[The Erd&amp;amp;#337;s discrepancy problem|Polymath5]]: The Erd&amp;amp;#337;s discrepancy problem. Proposed Jan 10, 2010; launched Jan 19, 2010.  Activity ceased by the end of 2012, but results from the project were used to solve the problem in 2015.&lt;br /&gt;
* [[imo 2010|Mini-polymath2]]: Solving Problem 5 the 2010 International Mathematical Olympiad.  Proposed Jun 12, 2010; launched and solved, Jul 8 2010.&lt;br /&gt;
* [[Improving the bounds for Roth&#039;s theorem|Polymath6]]: Improving the bounds for Roth&#039;s theorem. Proposed Feb 5, 2011.&lt;br /&gt;
* [[imo 2011|Mini-polymath3]]: Solving a problem from the 2011 International Mathematical Olympiad.  Proposed Jun 9, 2011; launched and solved, Jul 19, 2011.&lt;br /&gt;
* [[imo 2012|Mini-polymath4]]: Solving a problem from the 2012 International Mathematical Olympiad.  Proposed, Jun 3, 2012; launched, July 12 2012.&lt;br /&gt;
* [[The hot spots conjecture|Polymath7]]:  Establishing the Hot Spots conjecture for acute-angled triangles.  Proposed, May 31st, 2012; launched, Jun 8, 2012.&lt;br /&gt;
* [[Bounded gaps between primes|Polymath8]]: Improving the bounds for small gaps between primes.  Proposed, June 4, 2013; launched, June 4, 2013.  Research results have now been published.&lt;br /&gt;
* [[Discretized Borel Determinacy and P=NP|Polymath9]]: exploring Borel determinacy-based methods for giving complexity bounds.  Proposed, Oct 24, 2013; launched, Nov 3, 2013.&lt;br /&gt;
* [[The Erdos-Rado sunflower lemma|Polymath10]]: improving the bounds for the Erdos-Rado sunflower lemma.  Launched, Nov 2, 2015.&lt;br /&gt;
* [[Frankl&#039;s union-closed conjecture|Polymath11]]: proving Frankl&#039;s union-closed conjecture. Proposed Jan 21, 2016; launched Jan 29, 2016.  Concluded, Jan 17, 2017.&lt;br /&gt;
* [[Rota&#039;s conjecture|Polymath12]]: proving Rota&#039;s conjecture.  Proposed Feb 28, 2017.&lt;br /&gt;
* [[Intransitive dice|Polymath13]]: Intransitive dice.  Proposed Apr 28, 2017.&lt;br /&gt;
* [[linear norm|Polymath14]]: Classifying homogeneous norms on groups.  Initiated Dec 16, 2017; solved Dec 21, 2017.  Research results have now been published.&lt;br /&gt;
* [[De_Bruijn-Newman constant|Polymath15]]: Upper bounding the de Bruin-Newman constant.  Proposed, Jan 24 2018; launched Jan 27 2018.&lt;br /&gt;
* [[Hadwiger-Nelson problem|Polymath16]]: Simplifying the lower bound proof for the Hadwiger-Nelson problem.  Proposed, Apr 10, 2018; launched, Apr 14, 2018.&lt;br /&gt;
&lt;br /&gt;
== Polymath-like projects ==&lt;br /&gt;
&lt;br /&gt;
* Scott Aaronson&#039;s &amp;quot;philomath project&amp;quot;: &amp;quot;[http://scottaaronson.com/blog/?p=453 Sensitivity vs. Block sensitivity]&amp;quot; (see also [http://mathoverflow.net/questions/31482/the-sensitivity-of-2-colorings-of-the-d-dimensional-integer-lattice this Math Overflow question]).  Launched Jul 13, 2010.&lt;br /&gt;
* A wiki page clearinghouse for the [[Deolalikar P vs NP paper]].  Launched Aug 10, 2010.&lt;br /&gt;
* &amp;lt;del&amp;gt;[http://researchtrends.wikia.com/wiki/Main_Page Math Research Trends Wiki] &amp;quot;research in the middle&amp;quot;&amp;lt;/del&amp;gt; This project is recommended to be discontinued in favor of &amp;lt;b&amp;gt;[https://conference.portonvictor.org/wiki/Research_in_the_middle Research in the middle project] at [https://conference.portonvictor.org Virtual scientific conference]&amp;lt;/b&amp;gt;.&lt;br /&gt;
* The page for the [[ABC conjecture]] contains links and information about Mochizuki&#039;s claimed proof of this conjecture.&lt;br /&gt;
&lt;br /&gt;
== Proposed polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [http://gilkalai.wordpress.com/2009/03/25/an-open-discussion-and-polls-around-roths-theorem/ The cap set problem].  Proposed March 25, 2009 (see also these [http://gilkalai.wordpress.com/2009/05/11/around-the-cap-set-problem-b/ two] [http://gilkalai.wordpress.com/2009/05/18/the-cap-set-problem-and-frankl-rodl-theorem-c/ followup] posts).&lt;br /&gt;
* [[Boshernitzan’s problem]].  Proposed July 27, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/09/16/possible-future-polymath-projects/ Possible future polymath projects].  Discussion opened September 16, 2009.&lt;br /&gt;
* [http://rjlipton.wordpress.com/2011/05/12/a-possible-polymath-project/ A possible polymath project:] Proposal by Richard Lipton to attack a conjecture due to Erdos, about a class of Diophantine equations.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
A (partial) list of proposed projects can be found [http://polymathprojects.org/category/polymath-proposals/ here].&lt;br /&gt;
&lt;br /&gt;
If you have a tentative proposal for a polymath project, you can either make a post on it on your own blog, or place it [[other proposed projects|here]].&lt;br /&gt;
&lt;br /&gt;
== Discussions about polymath ==&lt;br /&gt;
&lt;br /&gt;
* [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?] Tim Gowers, January 27, 2009.&lt;br /&gt;
* [http://lucatrevisan.wordpress.com/2009/02/01/a-peoples-history-of-mathematics/ A people&#039;s history of mathematics] Luca Trevisan, February 1, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=553 The polymath project] Michael Nielsen, February 3, 2009.&lt;br /&gt;
* [http://www.neverendingbooks.org/index.php/yet-another-math20-proposal.html Yet another math 2.0 proposal] Lieven le Bruyn, February 11, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/10/polymath1-and-open-collaborative-mathematics/ Polymath1 and open collaborative mathematics] Tim Gowers, March 10, 2009.&lt;br /&gt;
* [http://maxwelldemon.com/2009/03/14/polymath/ Polymath] Edmund Harriss, March 14, 2009.&lt;br /&gt;
* [http://science.slashdot.org/article.pl?sid=09/03/18/194228 Massive open collaboration in mathematics declared a success] Slashdot, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=581 How changing the technology of collaboration can change the nature of collaboration] Michael Nielsen, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=584 The polymath project: scope of participation] Michael Nielsen, March 20, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/24/can-polymath-be-scaled-up/ Can polymath be scaled up?] Tim Gowers, March 24, 2009.&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/03/24/concluding-notes-on-the-polymath-project-and-a-challenge/ Concluding notes on the polymath project - and a challenge] Vilpulniak, March 24, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/on-scaling-up-the-polymath-project/ On scaling up the polymath project] Michael Nielsen, March 25, 2009.&lt;br /&gt;
* [http://numberwarrior.wordpress.com/2009/03/25/a-gentle-introduction-to-the-polymath-project/ A gentle introduction to the polymath project] Jason Dyer, March 25, 2009.&lt;br /&gt;
* [http://blogs.telegraph.co.uk/technology/iandouglas/9656357/tim_gowers_and_the_polymaths/ Tim Gowers and the polymaths] Ian Douglas (the Telegraph), April 29, 2009&lt;br /&gt;
* [http://terrytao.wordpress.com/2009/07/22/imo-2009-q6-mini-polymath-project-impressions-reflections-analysis/ IMO 2009 Q6 as mini-polymath project: impressions, reflections, analysis] Terence Tao, July 22, 2009.&lt;br /&gt;
* [http://polymathprojects.org/2009/07/27/selecting-the-next-polymath-project/ Selecting the next polymath project] Terence Tao, July 27, 2009.&lt;br /&gt;
* [http://blog.jonudell.net/2009/07/31/polymath-equals-user-innovatio/ Polymath equals user innovation] Jon Udell, July 31, 2009.&lt;br /&gt;
* [http://scienceblogs.com/christinaslisrant/2009/08/an_overview_of_the_polymath_pr.php An overview of the polymath project] Christina Pikas, August 1, 2009 &lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/08/09/collaborative-mathematics-etc/ Collaborative mathematics etc.] Vipulniak, August 9, 2009&lt;br /&gt;
* [http://www.nature.com/nature/journal/v461/n7266/full/461879a.html Massively collaborative mathematics] Tim Gowers, Michael Nielsen, Nature, October 15, 2009&lt;br /&gt;
* [http://portonmath.wordpress.com/2009/10/25/collaborative-research-of-filters/ Collaborative math research – a real example] Victor Porton, October 24, 2009&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/10/26/polymath-again/ Polymath again] Vipulniak, October 26, 2009&lt;br /&gt;
* [http://www.kennislink.nl/publicaties/wiskunde-met-zijn-allen Wiskunde met zijn allen] (Dutch), Alex van den Brandhof, Kennislink, November 12, 2009&lt;br /&gt;
* [http://www.sciencenews.org/view/generic/id/50532/title/Mathematics_by_collaboration Mathematics by collaboration], Julie Rehmeyer, ScienceNews, December 8, 2009&lt;br /&gt;
* [http://www.nytimes.com/projects/magazine/ideas/2009/#m Massively Collaborative Mathematics], Jordan Ellenberg, The Ninth Annual Year in Ideas, New York Times, 2009.&lt;br /&gt;
* [http://www.hypios.com/thinking/2010/01/13/massively-collaborative-mathematics-lessons-from-polymath1/ Massively Collaborative Mathematics: lessons from polymath1], Hypios, Jan 13 2010&lt;br /&gt;
* [http://ths1104.wordpress.com/2010/02/13/open-reflexions-sur-fond-de-polymaths/ Open réflexions sur fond de Polymaths] (French), ths1104, Feb 13 2010&lt;br /&gt;
* [http://www.javiertordable.com/blog/2010/02/25/collaborative-mathematics-future-of-science Collaborative Mathematics and The Future of Science] Javier Tordable, February 26 2010&lt;br /&gt;
* [http://www.scientificamerican.com/article.cfm?id=problem-solved-tic-tac-toe-blog Problem Solved, LOL: A Complex Tic-Tac-Toe Puzzle Falls Thanks to Blog Comments] Davide Castelvecchi, Scientific American, March 17 2010&lt;br /&gt;
* [http://www.thebigquestions.com/2010/04/08/blogging-tic-tac-toe-and-the-future-of-math/ Blogging, Tic Tac Toe, and the Future of Math] Steve Landsburg, The Big Questions, April 4 2010&lt;br /&gt;
* [http://www.siam.org/news/news.php?issue=0043.03 Massively Collaborative Mathematics] Julie Rehmeyer, SIAM News, Volume 43(3), April 2010 (to appear)&lt;br /&gt;
* [http://mbarany.com/publications.html#WikiSymPolymath  `But this is blog maths and we&#039;re free to make up conventions as we go along&#039;: Polymath1 and the Modalities of `Massively Collaborative Mathematics.&#039;] Michael Barany,  Proceedings of the 6th International Symposium on Wikis and Open Collaboration, Gdansk, Poland, 2010.&lt;br /&gt;
* [http://www.cs.cmu.edu/~jcransh/papers/cranshaw_kittur.pdf J. Cranshaw and A. Kittur. The Polymath Project: Lessons from a successful online collaboration in mathematics]. In Proceedings of the Conference on Human Factors in Computing Systems, Vancouver, BC, Canada, May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028113.900-how-to-build-the-global-mathematics-brain.html How to build the global mathematics brain], Jacob Aron, New Scientist, 4 May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028112.900-mathematics-becomes-more-sociable.html Mathematics becomes more sociable], New Scientist, 5 May 2011.&lt;br /&gt;
* [http://polymathprojects.files.wordpress.com/2011/03/polymathias.jpg Mathematical Advances: Lone or Massively Collaborative Endeavors?] from IAS Institute Letter for fall 2010 based on a discussion organized by IAS fall 2010.&lt;br /&gt;
* [http://today.uconn.edu/blog/2010/10/will-crowdsourcing-revolutionize-scholarship Will ‘Crowdsourcing’ Revolutionize Scholarship?] An article in UConn Today by Jeremy Teitelbaum, Fall 2010.&lt;br /&gt;
* [http://online.wsj.com/article/SB10001424052970204644504576653573191370088.html The New Einsteins Will Be Scientists Who Share] The Wall street journal, October 2011.&lt;br /&gt;
* [http://www.nature.com/news/parallel-lines-1.14759?WT.ec_id=NATURE-20140227 Parallel lines], editorial, Nature 506, 407–408 (27 February 2014).&lt;br /&gt;
Additional links are very welcome.&lt;br /&gt;
&lt;br /&gt;
== Other links ==&lt;br /&gt;
&lt;br /&gt;
* [http://polymathprojects.org/ The polymath blog]&lt;br /&gt;
* [http://polymathprojects.org/general-polymath-rules/ General polymath rules]&lt;br /&gt;
&lt;br /&gt;
== Note on anonymous editing ==&lt;br /&gt;
&lt;br /&gt;
To help combat spam, anonymous editing has been disabled, and a captcha system added to hinder automated account creation. If this is causing problems, please email mn@michaelnielsen.org.&lt;br /&gt;
&lt;br /&gt;
== Note on image uploads ==&lt;br /&gt;
&lt;br /&gt;
Image uploads have been disabled, as they were causing problems with spam.  If you&#039;d like to upload an image, please email mn@michaelnielsen.org&lt;/div&gt;</summary>
		<author><name>Khare</name></author>
	</entry>
	<entry>
		<id>https://michaelnielsen.org/polymath/index.php?title=Main_Page&amp;diff=10947</id>
		<title>Main Page</title>
		<link rel="alternate" type="text/html" href="https://michaelnielsen.org/polymath/index.php?title=Main_Page&amp;diff=10947"/>
		<updated>2018-11-27T18:09:57Z</updated>

		<summary type="html">&lt;p&gt;Khare: Undo revision 10944 by Khare (talk)&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{RightTOC}}&lt;br /&gt;
This is the wiki for &#039;&#039;polymath&#039;&#039; projects - massively collaborative online mathematical projects.  The idea of such projects originated in Tim Gowers&#039; blog post [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?]&lt;br /&gt;
&lt;br /&gt;
Many polymath projects will be proposed, planned, and run at [http://polymathprojects.org/ This Blog].&lt;br /&gt;
&lt;br /&gt;
A Polymath [[logo]] is being trialled.  If you have more suggestions, please add them to the [[logo]] page, or add to the discussion at [[Talk:logo]].&lt;br /&gt;
&lt;br /&gt;
The wiki is currently locked down due to a major influx of spam (July 29, 2013).  Please email mn@michaelnielsen.org if you&#039;d like an account set up, and I&#039;ll do my best to reply quickly. &lt;br /&gt;
&lt;br /&gt;
== Existing polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [[Polymath1]]: New proofs and bounds for the density Hales-Jewett theorem.  Initiated Feb 1, 2009; research results have now been published.&lt;br /&gt;
* [[Definable Banach Spaces|Polymath2]]: Must an “explicitly defined” Banach space contain &amp;lt;math&amp;gt;c_0&amp;lt;/math&amp;gt; or &amp;lt;math&amp;gt;l_p&amp;lt;/math&amp;gt;?  Initiated Feb 17, 2009; attempts to relaunch via wiki, June 9 2010.&lt;br /&gt;
* [[imo 2009 q6|Mini-polymath1]]: Solving Problem 6 of the 2009 International Mathematical Olympiad.  Initiated July 20, 2009; five proofs obtained so far.&lt;br /&gt;
* [[The polynomial Hirsch conjecture|Polymath3]].  The polynomial Hirsch conjecture.  Proposed July 17, 2009; launched, September 30, 2010.  &lt;br /&gt;
* [[finding primes|Polymath4]]: A deterministic way to find primes.  Proposed July 27, 2009; launched Aug 9, 2009.  Research results have now been published.&lt;br /&gt;
* [[The Erd&amp;amp;#337;s discrepancy problem|Polymath5]]: The Erd&amp;amp;#337;s discrepancy problem. Proposed Jan 10, 2010; launched Jan 19, 2010.  Activity ceased by the end of 2012, but results from the project were used to solve the problem in 2015.&lt;br /&gt;
* [[imo 2010|Mini-polymath2]]: Solving Problem 5 the 2010 International Mathematical Olympiad.  Proposed Jun 12, 2010; launched and solved, Jul 8 2010.&lt;br /&gt;
* [[Improving the bounds for Roth&#039;s theorem|Polymath6]]: Improving the bounds for Roth&#039;s theorem. Proposed Feb 5, 2011.&lt;br /&gt;
* [[imo 2011|Mini-polymath3]]: Solving a problem from the 2011 International Mathematical Olympiad.  Proposed Jun 9, 2011; launched and solved, Jul 19, 2011.&lt;br /&gt;
* [[imo 2012|Mini-polymath4]]: Solving a problem from the 2012 International Mathematical Olympiad.  Proposed, Jun 3, 2012; launched, July 12 2012.&lt;br /&gt;
* [[The hot spots conjecture|Polymath7]]:  Establishing the Hot Spots conjecture for acute-angled triangles.  Proposed, May 31st, 2012; launched, Jun 8, 2012.&lt;br /&gt;
* [[Bounded gaps between primes|Polymath8]]: Improving the bounds for small gaps between primes.  Proposed, June 4, 2013; launched, June 4, 2013.  Research results have now been published.&lt;br /&gt;
* [[Discretized Borel Determinacy and P=NP|Polymath9]]: exploring Borel determinacy-based methods for giving complexity bounds.  Proposed, Oct 24, 2013; launched, Nov 3, 2013.&lt;br /&gt;
* [[The Erdos-Rado sunflower lemma|Polymath10]]: improving the bounds for the Erdos-Rado sunflower lemma.  Launched, Nov 2, 2015.&lt;br /&gt;
* [[Frankl&#039;s union-closed conjecture|Polymath11]]: proving Frankl&#039;s union-closed conjecture. Proposed Jan 21, 2016; launched Jan 29, 2016.  Concluded, Jan 17, 2017.&lt;br /&gt;
* [[Rota&#039;s conjecture|Polymath12]]: proving Rota&#039;s conjecture.  Proposed Feb 28, 2017.&lt;br /&gt;
* [[Intransitive dice|Polymath13]]: Intransitive dice.  Proposed Apr 28, 2017.&lt;br /&gt;
* [[linear norm|Polymath14]]: Classifying homogeneous norms on groups.  Initiated Dec 16, 2017.  Results submitted, Jan 11, 2018.&lt;br /&gt;
* [[De_Bruijn-Newman constant|Polymath15]]: Upper bounding the de Bruin-Newman constant.  Proposed, Jan 24 2018; launched Jan 27 2018.&lt;br /&gt;
* [[Hadwiger-Nelson problem|Polymath16]]: Simplifying the lower bound proof for the Hadwiger-Nelson problem.  Proposed, Apr 10, 2018; launched, Apr 14, 2018.&lt;br /&gt;
&lt;br /&gt;
== Polymath-like projects ==&lt;br /&gt;
&lt;br /&gt;
* Scott Aaronson&#039;s &amp;quot;philomath project&amp;quot;: &amp;quot;[http://scottaaronson.com/blog/?p=453 Sensitivity vs. Block sensitivity]&amp;quot; (see also [http://mathoverflow.net/questions/31482/the-sensitivity-of-2-colorings-of-the-d-dimensional-integer-lattice this Math Overflow question]).  Launched Jul 13, 2010.&lt;br /&gt;
* A wiki page clearinghouse for the [[Deolalikar P vs NP paper]].  Launched Aug 10, 2010.&lt;br /&gt;
* &amp;lt;del&amp;gt;[http://researchtrends.wikia.com/wiki/Main_Page Math Research Trends Wiki] &amp;quot;research in the middle&amp;quot;&amp;lt;/del&amp;gt; This project is recommended to be discontinued in favor of &amp;lt;b&amp;gt;[https://conference.portonvictor.org/wiki/Research_in_the_middle Research in the middle project] at [https://conference.portonvictor.org Virtual scientific conference]&amp;lt;/b&amp;gt;.&lt;br /&gt;
* The page for the [[ABC conjecture]] contains links and information about Mochizuki&#039;s claimed proof of this conjecture.&lt;br /&gt;
&lt;br /&gt;
== Proposed polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [http://gilkalai.wordpress.com/2009/03/25/an-open-discussion-and-polls-around-roths-theorem/ The cap set problem].  Proposed March 25, 2009 (see also these [http://gilkalai.wordpress.com/2009/05/11/around-the-cap-set-problem-b/ two] [http://gilkalai.wordpress.com/2009/05/18/the-cap-set-problem-and-frankl-rodl-theorem-c/ followup] posts).&lt;br /&gt;
* [[Boshernitzan’s problem]].  Proposed July 27, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/09/16/possible-future-polymath-projects/ Possible future polymath projects].  Discussion opened September 16, 2009.&lt;br /&gt;
* [http://rjlipton.wordpress.com/2011/05/12/a-possible-polymath-project/ A possible polymath project:] Proposal by Richard Lipton to attack a conjecture due to Erdos, about a class of Diophantine equations.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
A (partial) list of proposed projects can be found [http://polymathprojects.org/category/polymath-proposals/ here].&lt;br /&gt;
&lt;br /&gt;
If you have a tentative proposal for a polymath project, you can either make a post on it on your own blog, or place it [[other proposed projects|here]].&lt;br /&gt;
&lt;br /&gt;
== Discussions about polymath ==&lt;br /&gt;
&lt;br /&gt;
* [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?] Tim Gowers, January 27, 2009.&lt;br /&gt;
* [http://lucatrevisan.wordpress.com/2009/02/01/a-peoples-history-of-mathematics/ A people&#039;s history of mathematics] Luca Trevisan, February 1, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=553 The polymath project] Michael Nielsen, February 3, 2009.&lt;br /&gt;
* [http://www.neverendingbooks.org/index.php/yet-another-math20-proposal.html Yet another math 2.0 proposal] Lieven le Bruyn, February 11, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/10/polymath1-and-open-collaborative-mathematics/ Polymath1 and open collaborative mathematics] Tim Gowers, March 10, 2009.&lt;br /&gt;
* [http://maxwelldemon.com/2009/03/14/polymath/ Polymath] Edmund Harriss, March 14, 2009.&lt;br /&gt;
* [http://science.slashdot.org/article.pl?sid=09/03/18/194228 Massive open collaboration in mathematics declared a success] Slashdot, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=581 How changing the technology of collaboration can change the nature of collaboration] Michael Nielsen, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=584 The polymath project: scope of participation] Michael Nielsen, March 20, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/24/can-polymath-be-scaled-up/ Can polymath be scaled up?] Tim Gowers, March 24, 2009.&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/03/24/concluding-notes-on-the-polymath-project-and-a-challenge/ Concluding notes on the polymath project - and a challenge] Vilpulniak, March 24, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/on-scaling-up-the-polymath-project/ On scaling up the polymath project] Michael Nielsen, March 25, 2009.&lt;br /&gt;
* [http://numberwarrior.wordpress.com/2009/03/25/a-gentle-introduction-to-the-polymath-project/ A gentle introduction to the polymath project] Jason Dyer, March 25, 2009.&lt;br /&gt;
* [http://blogs.telegraph.co.uk/technology/iandouglas/9656357/tim_gowers_and_the_polymaths/ Tim Gowers and the polymaths] Ian Douglas (the Telegraph), April 29, 2009&lt;br /&gt;
* [http://terrytao.wordpress.com/2009/07/22/imo-2009-q6-mini-polymath-project-impressions-reflections-analysis/ IMO 2009 Q6 as mini-polymath project: impressions, reflections, analysis] Terence Tao, July 22, 2009.&lt;br /&gt;
* [http://polymathprojects.org/2009/07/27/selecting-the-next-polymath-project/ Selecting the next polymath project] Terence Tao, July 27, 2009.&lt;br /&gt;
* [http://blog.jonudell.net/2009/07/31/polymath-equals-user-innovatio/ Polymath equals user innovation] Jon Udell, July 31, 2009.&lt;br /&gt;
* [http://scienceblogs.com/christinaslisrant/2009/08/an_overview_of_the_polymath_pr.php An overview of the polymath project] Christina Pikas, August 1, 2009 &lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/08/09/collaborative-mathematics-etc/ Collaborative mathematics etc.] Vipulniak, August 9, 2009&lt;br /&gt;
* [http://www.nature.com/nature/journal/v461/n7266/full/461879a.html Massively collaborative mathematics] Tim Gowers, Michael Nielsen, Nature, October 15, 2009&lt;br /&gt;
* [http://portonmath.wordpress.com/2009/10/25/collaborative-research-of-filters/ Collaborative math research – a real example] Victor Porton, October 24, 2009&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/10/26/polymath-again/ Polymath again] Vipulniak, October 26, 2009&lt;br /&gt;
* [http://www.kennislink.nl/publicaties/wiskunde-met-zijn-allen Wiskunde met zijn allen] (Dutch), Alex van den Brandhof, Kennislink, November 12, 2009&lt;br /&gt;
* [http://www.sciencenews.org/view/generic/id/50532/title/Mathematics_by_collaboration Mathematics by collaboration], Julie Rehmeyer, ScienceNews, December 8, 2009&lt;br /&gt;
* [http://www.nytimes.com/projects/magazine/ideas/2009/#m Massively Collaborative Mathematics], Jordan Ellenberg, The Ninth Annual Year in Ideas, New York Times, 2009.&lt;br /&gt;
* [http://www.hypios.com/thinking/2010/01/13/massively-collaborative-mathematics-lessons-from-polymath1/ Massively Collaborative Mathematics: lessons from polymath1], Hypios, Jan 13 2010&lt;br /&gt;
* [http://ths1104.wordpress.com/2010/02/13/open-reflexions-sur-fond-de-polymaths/ Open réflexions sur fond de Polymaths] (French), ths1104, Feb 13 2010&lt;br /&gt;
* [http://www.javiertordable.com/blog/2010/02/25/collaborative-mathematics-future-of-science Collaborative Mathematics and The Future of Science] Javier Tordable, February 26 2010&lt;br /&gt;
* [http://www.scientificamerican.com/article.cfm?id=problem-solved-tic-tac-toe-blog Problem Solved, LOL: A Complex Tic-Tac-Toe Puzzle Falls Thanks to Blog Comments] Davide Castelvecchi, Scientific American, March 17 2010&lt;br /&gt;
* [http://www.thebigquestions.com/2010/04/08/blogging-tic-tac-toe-and-the-future-of-math/ Blogging, Tic Tac Toe, and the Future of Math] Steve Landsburg, The Big Questions, April 4 2010&lt;br /&gt;
* [http://www.siam.org/news/news.php?issue=0043.03 Massively Collaborative Mathematics] Julie Rehmeyer, SIAM News, Volume 43(3), April 2010 (to appear)&lt;br /&gt;
* [http://mbarany.com/publications.html#WikiSymPolymath  `But this is blog maths and we&#039;re free to make up conventions as we go along&#039;: Polymath1 and the Modalities of `Massively Collaborative Mathematics.&#039;] Michael Barany,  Proceedings of the 6th International Symposium on Wikis and Open Collaboration, Gdansk, Poland, 2010.&lt;br /&gt;
* [http://www.cs.cmu.edu/~jcransh/papers/cranshaw_kittur.pdf J. Cranshaw and A. Kittur. The Polymath Project: Lessons from a successful online collaboration in mathematics]. In Proceedings of the Conference on Human Factors in Computing Systems, Vancouver, BC, Canada, May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028113.900-how-to-build-the-global-mathematics-brain.html How to build the global mathematics brain], Jacob Aron, New Scientist, 4 May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028112.900-mathematics-becomes-more-sociable.html Mathematics becomes more sociable], New Scientist, 5 May 2011.&lt;br /&gt;
* [http://polymathprojects.files.wordpress.com/2011/03/polymathias.jpg Mathematical Advances: Lone or Massively Collaborative Endeavors?] from IAS Institute Letter for fall 2010 based on a discussion organized by IAS fall 2010.&lt;br /&gt;
* [http://today.uconn.edu/blog/2010/10/will-crowdsourcing-revolutionize-scholarship Will ‘Crowdsourcing’ Revolutionize Scholarship?] An article in UConn Today by Jeremy Teitelbaum, Fall 2010.&lt;br /&gt;
* [http://online.wsj.com/article/SB10001424052970204644504576653573191370088.html The New Einsteins Will Be Scientists Who Share] The Wall street journal, October 2011.&lt;br /&gt;
* [http://www.nature.com/news/parallel-lines-1.14759?WT.ec_id=NATURE-20140227 Parallel lines], editorial, Nature 506, 407–408 (27 February 2014).&lt;br /&gt;
Additional links are very welcome.&lt;br /&gt;
&lt;br /&gt;
== Other links ==&lt;br /&gt;
&lt;br /&gt;
* [http://polymathprojects.org/ The polymath blog]&lt;br /&gt;
* [http://polymathprojects.org/general-polymath-rules/ General polymath rules]&lt;br /&gt;
&lt;br /&gt;
== Note on anonymous editing ==&lt;br /&gt;
&lt;br /&gt;
To help combat spam, anonymous editing has been disabled, and a captcha system added to hinder automated account creation. If this is causing problems, please email mn@michaelnielsen.org.&lt;br /&gt;
&lt;br /&gt;
== Note on image uploads ==&lt;br /&gt;
&lt;br /&gt;
Image uploads have been disabled, as they were causing problems with spam.  If you&#039;d like to upload an image, please email mn@michaelnielsen.org&lt;/div&gt;</summary>
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This is the wiki for &#039;&#039;polymath&#039;&#039; projects - massively collaborative online mathematical projects.  The idea of such projects originated in Tim Gowers&#039; blog post [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?]&lt;br /&gt;
&lt;br /&gt;
Many polymath projects will be proposed, planned, and run at [http://polymathprojects.org/ This Blog].&lt;br /&gt;
&lt;br /&gt;
A Polymath [[logo]] is being trialled.  If you have more suggestions, please add them to the [[logo]] page, or add to the discussion at [[Talk:logo]].&lt;br /&gt;
&lt;br /&gt;
The wiki is currently locked down due to a major influx of spam (July 29, 2013).  Please email mn@michaelnielsen.org if you&#039;d like an account set up, and I&#039;ll do my best to reply quickly. &lt;br /&gt;
&lt;br /&gt;
== Existing polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [[Polymath1]]: New proofs and bounds for the density Hales-Jewett theorem.  Initiated Feb 1, 2009; research results have now been published.&lt;br /&gt;
* [[Definable Banach Spaces|Polymath2]]: Must an “explicitly defined” Banach space contain &amp;lt;math&amp;gt;c_0&amp;lt;/math&amp;gt; or &amp;lt;math&amp;gt;l_p&amp;lt;/math&amp;gt;?  Initiated Feb 17, 2009; attempts to relaunch via wiki, June 9 2010.&lt;br /&gt;
* [[imo 2009 q6|Mini-polymath1]]: Solving Problem 6 of the 2009 International Mathematical Olympiad.  Initiated July 20, 2009; five proofs obtained so far.&lt;br /&gt;
* [[The polynomial Hirsch conjecture|Polymath3]].  The polynomial Hirsch conjecture.  Proposed July 17, 2009; launched, September 30, 2010.  &lt;br /&gt;
* [[finding primes|Polymath4]]: A deterministic way to find primes.  Proposed July 27, 2009; launched Aug 9, 2009.  Research results have now been published.&lt;br /&gt;
* [[The Erd&amp;amp;#337;s discrepancy problem|Polymath5]]: The Erd&amp;amp;#337;s discrepancy problem. Proposed Jan 10, 2010; launched Jan 19, 2010.  Activity ceased by the end of 2012, but results from the project were used to solve the problem in 2015.&lt;br /&gt;
* [[imo 2010|Mini-polymath2]]: Solving Problem 5 the 2010 International Mathematical Olympiad.  Proposed Jun 12, 2010; launched and solved, Jul 8 2010.&lt;br /&gt;
* [[Improving the bounds for Roth&#039;s theorem|Polymath6]]: Improving the bounds for Roth&#039;s theorem. Proposed Feb 5, 2011.&lt;br /&gt;
* [[imo 2011|Mini-polymath3]]: Solving a problem from the 2011 International Mathematical Olympiad.  Proposed Jun 9, 2011; launched and solved, Jul 19, 2011.&lt;br /&gt;
* [[imo 2012|Mini-polymath4]]: Solving a problem from the 2012 International Mathematical Olympiad.  Proposed, Jun 3, 2012; launched, July 12 2012.&lt;br /&gt;
* [[The hot spots conjecture|Polymath7]]:  Establishing the Hot Spots conjecture for acute-angled triangles.  Proposed, May 31st, 2012; launched, Jun 8, 2012.&lt;br /&gt;
* [[Bounded gaps between primes|Polymath8]]: Improving the bounds for small gaps between primes.  Proposed, June 4, 2013; launched, June 4, 2013.  Research results have now been published.&lt;br /&gt;
* [[Discretized Borel Determinacy and P=NP|Polymath9]]: exploring Borel determinacy-based methods for giving complexity bounds.  Proposed, Oct 24, 2013; launched, Nov 3, 2013.&lt;br /&gt;
* [[The Erdos-Rado sunflower lemma|Polymath10]]: improving the bounds for the Erdos-Rado sunflower lemma.  Launched, Nov 2, 2015.&lt;br /&gt;
* [[Frankl&#039;s union-closed conjecture|Polymath11]]: proving Frankl&#039;s union-closed conjecture. Proposed Jan 21, 2016; launched Jan 29, 2016.  Concluded, Jan 17, 2017.&lt;br /&gt;
* [[Rota&#039;s conjecture|Polymath12]]: proving Rota&#039;s conjecture.  Proposed Feb 28, 2017.&lt;br /&gt;
* [[Intransitive dice|Polymath13]]: Intransitive dice.  Proposed Apr 28, 2017.&lt;br /&gt;
* [[linear norm|Polymath14]]: Classifying homogeneous norms on groups.  Initiated Dec 16, 2017; solved Dec 21, 2017.  Research results have now been published.&lt;br /&gt;
* [[De_Bruijn-Newman constant|Polymath15]]: Upper bounding the de Bruin-Newman constant.  Proposed, Jan 24 2018; launched Jan 27 2018.&lt;br /&gt;
* [[Hadwiger-Nelson problem|Polymath16]]: Simplifying the lower bound proof for the Hadwiger-Nelson problem.  Proposed, Apr 10, 2018; launched, Apr 14, 2018.&lt;br /&gt;
&lt;br /&gt;
== Polymath-like projects ==&lt;br /&gt;
&lt;br /&gt;
* Scott Aaronson&#039;s &amp;quot;philomath project&amp;quot;: &amp;quot;[http://scottaaronson.com/blog/?p=453 Sensitivity vs. Block sensitivity]&amp;quot; (see also [http://mathoverflow.net/questions/31482/the-sensitivity-of-2-colorings-of-the-d-dimensional-integer-lattice this Math Overflow question]).  Launched Jul 13, 2010.&lt;br /&gt;
* A wiki page clearinghouse for the [[Deolalikar P vs NP paper]].  Launched Aug 10, 2010.&lt;br /&gt;
* &amp;lt;del&amp;gt;[http://researchtrends.wikia.com/wiki/Main_Page Math Research Trends Wiki] &amp;quot;research in the middle&amp;quot;&amp;lt;/del&amp;gt; This project is recommended to be discontinued in favor of &amp;lt;b&amp;gt;[https://conference.portonvictor.org/wiki/Research_in_the_middle Research in the middle project] at [https://conference.portonvictor.org Virtual scientific conference]&amp;lt;/b&amp;gt;.&lt;br /&gt;
* The page for the [[ABC conjecture]] contains links and information about Mochizuki&#039;s claimed proof of this conjecture.&lt;br /&gt;
&lt;br /&gt;
== Proposed polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [http://gilkalai.wordpress.com/2009/03/25/an-open-discussion-and-polls-around-roths-theorem/ The cap set problem].  Proposed March 25, 2009 (see also these [http://gilkalai.wordpress.com/2009/05/11/around-the-cap-set-problem-b/ two] [http://gilkalai.wordpress.com/2009/05/18/the-cap-set-problem-and-frankl-rodl-theorem-c/ followup] posts).&lt;br /&gt;
* [[Boshernitzan’s problem]].  Proposed July 27, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/09/16/possible-future-polymath-projects/ Possible future polymath projects].  Discussion opened September 16, 2009.&lt;br /&gt;
* [http://rjlipton.wordpress.com/2011/05/12/a-possible-polymath-project/ A possible polymath project:] Proposal by Richard Lipton to attack a conjecture due to Erdos, about a class of Diophantine equations.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
A (partial) list of proposed projects can be found [http://polymathprojects.org/category/polymath-proposals/ here].&lt;br /&gt;
&lt;br /&gt;
If you have a tentative proposal for a polymath project, you can either make a post on it on your own blog, or place it [[other proposed projects|here]].&lt;br /&gt;
&lt;br /&gt;
== Discussions about polymath ==&lt;br /&gt;
&lt;br /&gt;
* [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?] Tim Gowers, January 27, 2009.&lt;br /&gt;
* [http://lucatrevisan.wordpress.com/2009/02/01/a-peoples-history-of-mathematics/ A people&#039;s history of mathematics] Luca Trevisan, February 1, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=553 The polymath project] Michael Nielsen, February 3, 2009.&lt;br /&gt;
* [http://www.neverendingbooks.org/index.php/yet-another-math20-proposal.html Yet another math 2.0 proposal] Lieven le Bruyn, February 11, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/10/polymath1-and-open-collaborative-mathematics/ Polymath1 and open collaborative mathematics] Tim Gowers, March 10, 2009.&lt;br /&gt;
* [http://maxwelldemon.com/2009/03/14/polymath/ Polymath] Edmund Harriss, March 14, 2009.&lt;br /&gt;
* [http://science.slashdot.org/article.pl?sid=09/03/18/194228 Massive open collaboration in mathematics declared a success] Slashdot, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=581 How changing the technology of collaboration can change the nature of collaboration] Michael Nielsen, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=584 The polymath project: scope of participation] Michael Nielsen, March 20, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/24/can-polymath-be-scaled-up/ Can polymath be scaled up?] Tim Gowers, March 24, 2009.&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/03/24/concluding-notes-on-the-polymath-project-and-a-challenge/ Concluding notes on the polymath project - and a challenge] Vilpulniak, March 24, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/on-scaling-up-the-polymath-project/ On scaling up the polymath project] Michael Nielsen, March 25, 2009.&lt;br /&gt;
* [http://numberwarrior.wordpress.com/2009/03/25/a-gentle-introduction-to-the-polymath-project/ A gentle introduction to the polymath project] Jason Dyer, March 25, 2009.&lt;br /&gt;
* [http://blogs.telegraph.co.uk/technology/iandouglas/9656357/tim_gowers_and_the_polymaths/ Tim Gowers and the polymaths] Ian Douglas (the Telegraph), April 29, 2009&lt;br /&gt;
* [http://terrytao.wordpress.com/2009/07/22/imo-2009-q6-mini-polymath-project-impressions-reflections-analysis/ IMO 2009 Q6 as mini-polymath project: impressions, reflections, analysis] Terence Tao, July 22, 2009.&lt;br /&gt;
* [http://polymathprojects.org/2009/07/27/selecting-the-next-polymath-project/ Selecting the next polymath project] Terence Tao, July 27, 2009.&lt;br /&gt;
* [http://blog.jonudell.net/2009/07/31/polymath-equals-user-innovatio/ Polymath equals user innovation] Jon Udell, July 31, 2009.&lt;br /&gt;
* [http://scienceblogs.com/christinaslisrant/2009/08/an_overview_of_the_polymath_pr.php An overview of the polymath project] Christina Pikas, August 1, 2009 &lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/08/09/collaborative-mathematics-etc/ Collaborative mathematics etc.] Vipulniak, August 9, 2009&lt;br /&gt;
* [http://www.nature.com/nature/journal/v461/n7266/full/461879a.html Massively collaborative mathematics] Tim Gowers, Michael Nielsen, Nature, October 15, 2009&lt;br /&gt;
* [http://portonmath.wordpress.com/2009/10/25/collaborative-research-of-filters/ Collaborative math research – a real example] Victor Porton, October 24, 2009&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/10/26/polymath-again/ Polymath again] Vipulniak, October 26, 2009&lt;br /&gt;
* [http://www.kennislink.nl/publicaties/wiskunde-met-zijn-allen Wiskunde met zijn allen] (Dutch), Alex van den Brandhof, Kennislink, November 12, 2009&lt;br /&gt;
* [http://www.sciencenews.org/view/generic/id/50532/title/Mathematics_by_collaboration Mathematics by collaboration], Julie Rehmeyer, ScienceNews, December 8, 2009&lt;br /&gt;
* [http://www.nytimes.com/projects/magazine/ideas/2009/#m Massively Collaborative Mathematics], Jordan Ellenberg, The Ninth Annual Year in Ideas, New York Times, 2009.&lt;br /&gt;
* [http://www.hypios.com/thinking/2010/01/13/massively-collaborative-mathematics-lessons-from-polymath1/ Massively Collaborative Mathematics: lessons from polymath1], Hypios, Jan 13 2010&lt;br /&gt;
* [http://ths1104.wordpress.com/2010/02/13/open-reflexions-sur-fond-de-polymaths/ Open réflexions sur fond de Polymaths] (French), ths1104, Feb 13 2010&lt;br /&gt;
* [http://www.javiertordable.com/blog/2010/02/25/collaborative-mathematics-future-of-science Collaborative Mathematics and The Future of Science] Javier Tordable, February 26 2010&lt;br /&gt;
* [http://www.scientificamerican.com/article.cfm?id=problem-solved-tic-tac-toe-blog Problem Solved, LOL: A Complex Tic-Tac-Toe Puzzle Falls Thanks to Blog Comments] Davide Castelvecchi, Scientific American, March 17 2010&lt;br /&gt;
* [http://www.thebigquestions.com/2010/04/08/blogging-tic-tac-toe-and-the-future-of-math/ Blogging, Tic Tac Toe, and the Future of Math] Steve Landsburg, The Big Questions, April 4 2010&lt;br /&gt;
* [http://www.siam.org/news/news.php?issue=0043.03 Massively Collaborative Mathematics] Julie Rehmeyer, SIAM News, Volume 43(3), April 2010 (to appear)&lt;br /&gt;
* [http://mbarany.com/publications.html#WikiSymPolymath  `But this is blog maths and we&#039;re free to make up conventions as we go along&#039;: Polymath1 and the Modalities of `Massively Collaborative Mathematics.&#039;] Michael Barany,  Proceedings of the 6th International Symposium on Wikis and Open Collaboration, Gdansk, Poland, 2010.&lt;br /&gt;
* [http://www.cs.cmu.edu/~jcransh/papers/cranshaw_kittur.pdf J. Cranshaw and A. Kittur. The Polymath Project: Lessons from a successful online collaboration in mathematics]. In Proceedings of the Conference on Human Factors in Computing Systems, Vancouver, BC, Canada, May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028113.900-how-to-build-the-global-mathematics-brain.html How to build the global mathematics brain], Jacob Aron, New Scientist, 4 May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028112.900-mathematics-becomes-more-sociable.html Mathematics becomes more sociable], New Scientist, 5 May 2011.&lt;br /&gt;
* [http://polymathprojects.files.wordpress.com/2011/03/polymathias.jpg Mathematical Advances: Lone or Massively Collaborative Endeavors?] from IAS Institute Letter for fall 2010 based on a discussion organized by IAS fall 2010.&lt;br /&gt;
* [http://today.uconn.edu/blog/2010/10/will-crowdsourcing-revolutionize-scholarship Will ‘Crowdsourcing’ Revolutionize Scholarship?] An article in UConn Today by Jeremy Teitelbaum, Fall 2010.&lt;br /&gt;
* [http://online.wsj.com/article/SB10001424052970204644504576653573191370088.html The New Einsteins Will Be Scientists Who Share] The Wall street journal, October 2011.&lt;br /&gt;
* [http://www.nature.com/news/parallel-lines-1.14759?WT.ec_id=NATURE-20140227 Parallel lines], editorial, Nature 506, 407–408 (27 February 2014).&lt;br /&gt;
Additional links are very welcome.&lt;br /&gt;
&lt;br /&gt;
== Other links ==&lt;br /&gt;
&lt;br /&gt;
* [http://polymathprojects.org/ The polymath blog]&lt;br /&gt;
* [http://polymathprojects.org/general-polymath-rules/ General polymath rules]&lt;br /&gt;
&lt;br /&gt;
== Note on anonymous editing ==&lt;br /&gt;
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To help combat spam, anonymous editing has been disabled, and a captcha system added to hinder automated account creation. If this is causing problems, please email mn@michaelnielsen.org.&lt;br /&gt;
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== Note on image uploads ==&lt;br /&gt;
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Image uploads have been disabled, as they were causing problems with spam.  If you&#039;d like to upload an image, please email mn@michaelnielsen.org&lt;/div&gt;</summary>
		<author><name>Khare</name></author>
	</entry>
	<entry>
		<id>https://michaelnielsen.org/polymath/index.php?title=Main_Page&amp;diff=10945</id>
		<title>Main Page</title>
		<link rel="alternate" type="text/html" href="https://michaelnielsen.org/polymath/index.php?title=Main_Page&amp;diff=10945"/>
		<updated>2018-11-27T18:08:16Z</updated>

		<summary type="html">&lt;p&gt;Khare: &lt;/p&gt;
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This is the wiki for &#039;&#039;polymath&#039;&#039; projects - massively collaborative online mathematical projects.  The idea of such projects originated in Tim Gowers&#039; blog post [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?]&lt;br /&gt;
&lt;br /&gt;
Many polymath projects will be proposed, planned, and run at [http://polymathprojects.org/ This Blog].&lt;br /&gt;
&lt;br /&gt;
A Polymath [[logo]] is being trialled.  If you have more suggestions, please add them to the [[logo]] page, or add to the discussion at [[Talk:logo]].&lt;br /&gt;
&lt;br /&gt;
The wiki is currently locked down due to a major influx of spam (July 29, 2013).  Please email mn@michaelnielsen.org if you&#039;d like an account set up, and I&#039;ll do my best to reply quickly. &lt;br /&gt;
&lt;br /&gt;
== Existing polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [[Polymath1]]: New proofs and bounds for the density Hales-Jewett theorem.  Initiated Feb 1, 2009; research results have now been published.&lt;br /&gt;
* [[Definable Banach Spaces|Polymath2]]: Must an “explicitly defined” Banach space contain &amp;lt;math&amp;gt;c_0&amp;lt;/math&amp;gt; or &amp;lt;math&amp;gt;l_p&amp;lt;/math&amp;gt;?  Initiated Feb 17, 2009; attempts to relaunch via wiki, June 9 2010.&lt;br /&gt;
* [[imo 2009 q6|Mini-polymath1]]: Solving Problem 6 of the 2009 International Mathematical Olympiad.  Initiated July 20, 2009; five proofs obtained so far.&lt;br /&gt;
* [[The polynomial Hirsch conjecture|Polymath3]].  The polynomial Hirsch conjecture.  Proposed July 17, 2009; launched, September 30, 2010.  &lt;br /&gt;
* [[finding primes|Polymath4]]: A deterministic way to find primes.  Proposed July 27, 2009; launched Aug 9, 2009.  Research results have now been published.&lt;br /&gt;
* [[The Erd&amp;amp;#337;s discrepancy problem|Polymath5]]: The Erd&amp;amp;#337;s discrepancy problem. Proposed Jan 10, 2010; launched Jan 19, 2010.  Activity ceased by the end of 2012, but results from the project were used to solve the problem in 2015.&lt;br /&gt;
* [[imo 2010|Mini-polymath2]]: Solving Problem 5 the 2010 International Mathematical Olympiad.  Proposed Jun 12, 2010; launched and solved, Jul 8 2010.&lt;br /&gt;
* [[Improving the bounds for Roth&#039;s theorem|Polymath6]]: Improving the bounds for Roth&#039;s theorem. Proposed Feb 5, 2011.&lt;br /&gt;
* [[imo 2011|Mini-polymath3]]: Solving a problem from the 2011 International Mathematical Olympiad.  Proposed Jun 9, 2011; launched and solved, Jul 19, 2011.&lt;br /&gt;
* [[imo 2012|Mini-polymath4]]: Solving a problem from the 2012 International Mathematical Olympiad.  Proposed, Jun 3, 2012; launched, July 12 2012.&lt;br /&gt;
* [[The hot spots conjecture|Polymath7]]:  Establishing the Hot Spots conjecture for acute-angled triangles.  Proposed, May 31st, 2012; launched, Jun 8, 2012.&lt;br /&gt;
* [[Bounded gaps between primes|Polymath8]]: Improving the bounds for small gaps between primes.  Proposed, June 4, 2013; launched, June 4, 2013.  Research results have now been published.&lt;br /&gt;
* [[Discretized Borel Determinacy and P=NP|Polymath9]]: exploring Borel determinacy-based methods for giving complexity bounds.  Proposed, Oct 24, 2013; launched, Nov 3, 2013.&lt;br /&gt;
* [[The Erdos-Rado sunflower lemma|Polymath10]]: improving the bounds for the Erdos-Rado sunflower lemma.  Launched, Nov 2, 2015.&lt;br /&gt;
* [[Frankl&#039;s union-closed conjecture|Polymath11]]: proving Frankl&#039;s union-closed conjecture. Proposed Jan 21, 2016; launched Jan 29, 2016.  Concluded, Jan 17, 2017.&lt;br /&gt;
* [[Rota&#039;s conjecture|Polymath12]]: proving Rota&#039;s conjecture.  Proposed Feb 28, 2017.&lt;br /&gt;
* [[Intransitive dice|Polymath13]]: Intransitive dice.  Proposed Apr 28, 2017.&lt;br /&gt;
* [[linear norm|Polymath14]]: Classifying homogeneous norms on groups.  Initiated Dec 16, 2017, 2017; solved Dec 21, 2017.  Research results have now been published.&lt;br /&gt;
* [[De_Bruijn-Newman constant|Polymath15]]: Upper bounding the de Bruin-Newman constant.  Proposed, Jan 24 2018; launched Jan 27 2018.&lt;br /&gt;
* [[Hadwiger-Nelson problem|Polymath16]]: Simplifying the lower bound proof for the Hadwiger-Nelson problem.  Proposed, Apr 10, 2018; launched, Apr 14, 2018.&lt;br /&gt;
&lt;br /&gt;
== Polymath-like projects ==&lt;br /&gt;
&lt;br /&gt;
* Scott Aaronson&#039;s &amp;quot;philomath project&amp;quot;: &amp;quot;[http://scottaaronson.com/blog/?p=453 Sensitivity vs. Block sensitivity]&amp;quot; (see also [http://mathoverflow.net/questions/31482/the-sensitivity-of-2-colorings-of-the-d-dimensional-integer-lattice this Math Overflow question]).  Launched Jul 13, 2010.&lt;br /&gt;
* A wiki page clearinghouse for the [[Deolalikar P vs NP paper]].  Launched Aug 10, 2010.&lt;br /&gt;
* &amp;lt;del&amp;gt;[http://researchtrends.wikia.com/wiki/Main_Page Math Research Trends Wiki] &amp;quot;research in the middle&amp;quot;&amp;lt;/del&amp;gt; This project is recommended to be discontinued in favor of &amp;lt;b&amp;gt;[https://conference.portonvictor.org/wiki/Research_in_the_middle Research in the middle project] at [https://conference.portonvictor.org Virtual scientific conference]&amp;lt;/b&amp;gt;.&lt;br /&gt;
* The page for the [[ABC conjecture]] contains links and information about Mochizuki&#039;s claimed proof of this conjecture.&lt;br /&gt;
&lt;br /&gt;
== Proposed polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [http://gilkalai.wordpress.com/2009/03/25/an-open-discussion-and-polls-around-roths-theorem/ The cap set problem].  Proposed March 25, 2009 (see also these [http://gilkalai.wordpress.com/2009/05/11/around-the-cap-set-problem-b/ two] [http://gilkalai.wordpress.com/2009/05/18/the-cap-set-problem-and-frankl-rodl-theorem-c/ followup] posts).&lt;br /&gt;
* [[Boshernitzan’s problem]].  Proposed July 27, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/09/16/possible-future-polymath-projects/ Possible future polymath projects].  Discussion opened September 16, 2009.&lt;br /&gt;
* [http://rjlipton.wordpress.com/2011/05/12/a-possible-polymath-project/ A possible polymath project:] Proposal by Richard Lipton to attack a conjecture due to Erdos, about a class of Diophantine equations.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
A (partial) list of proposed projects can be found [http://polymathprojects.org/category/polymath-proposals/ here].&lt;br /&gt;
&lt;br /&gt;
If you have a tentative proposal for a polymath project, you can either make a post on it on your own blog, or place it [[other proposed projects|here]].&lt;br /&gt;
&lt;br /&gt;
== Discussions about polymath ==&lt;br /&gt;
&lt;br /&gt;
* [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?] Tim Gowers, January 27, 2009.&lt;br /&gt;
* [http://lucatrevisan.wordpress.com/2009/02/01/a-peoples-history-of-mathematics/ A people&#039;s history of mathematics] Luca Trevisan, February 1, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=553 The polymath project] Michael Nielsen, February 3, 2009.&lt;br /&gt;
* [http://www.neverendingbooks.org/index.php/yet-another-math20-proposal.html Yet another math 2.0 proposal] Lieven le Bruyn, February 11, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/10/polymath1-and-open-collaborative-mathematics/ Polymath1 and open collaborative mathematics] Tim Gowers, March 10, 2009.&lt;br /&gt;
* [http://maxwelldemon.com/2009/03/14/polymath/ Polymath] Edmund Harriss, March 14, 2009.&lt;br /&gt;
* [http://science.slashdot.org/article.pl?sid=09/03/18/194228 Massive open collaboration in mathematics declared a success] Slashdot, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=581 How changing the technology of collaboration can change the nature of collaboration] Michael Nielsen, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=584 The polymath project: scope of participation] Michael Nielsen, March 20, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/24/can-polymath-be-scaled-up/ Can polymath be scaled up?] Tim Gowers, March 24, 2009.&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/03/24/concluding-notes-on-the-polymath-project-and-a-challenge/ Concluding notes on the polymath project - and a challenge] Vilpulniak, March 24, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/on-scaling-up-the-polymath-project/ On scaling up the polymath project] Michael Nielsen, March 25, 2009.&lt;br /&gt;
* [http://numberwarrior.wordpress.com/2009/03/25/a-gentle-introduction-to-the-polymath-project/ A gentle introduction to the polymath project] Jason Dyer, March 25, 2009.&lt;br /&gt;
* [http://blogs.telegraph.co.uk/technology/iandouglas/9656357/tim_gowers_and_the_polymaths/ Tim Gowers and the polymaths] Ian Douglas (the Telegraph), April 29, 2009&lt;br /&gt;
* [http://terrytao.wordpress.com/2009/07/22/imo-2009-q6-mini-polymath-project-impressions-reflections-analysis/ IMO 2009 Q6 as mini-polymath project: impressions, reflections, analysis] Terence Tao, July 22, 2009.&lt;br /&gt;
* [http://polymathprojects.org/2009/07/27/selecting-the-next-polymath-project/ Selecting the next polymath project] Terence Tao, July 27, 2009.&lt;br /&gt;
* [http://blog.jonudell.net/2009/07/31/polymath-equals-user-innovatio/ Polymath equals user innovation] Jon Udell, July 31, 2009.&lt;br /&gt;
* [http://scienceblogs.com/christinaslisrant/2009/08/an_overview_of_the_polymath_pr.php An overview of the polymath project] Christina Pikas, August 1, 2009 &lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/08/09/collaborative-mathematics-etc/ Collaborative mathematics etc.] Vipulniak, August 9, 2009&lt;br /&gt;
* [http://www.nature.com/nature/journal/v461/n7266/full/461879a.html Massively collaborative mathematics] Tim Gowers, Michael Nielsen, Nature, October 15, 2009&lt;br /&gt;
* [http://portonmath.wordpress.com/2009/10/25/collaborative-research-of-filters/ Collaborative math research – a real example] Victor Porton, October 24, 2009&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/10/26/polymath-again/ Polymath again] Vipulniak, October 26, 2009&lt;br /&gt;
* [http://www.kennislink.nl/publicaties/wiskunde-met-zijn-allen Wiskunde met zijn allen] (Dutch), Alex van den Brandhof, Kennislink, November 12, 2009&lt;br /&gt;
* [http://www.sciencenews.org/view/generic/id/50532/title/Mathematics_by_collaboration Mathematics by collaboration], Julie Rehmeyer, ScienceNews, December 8, 2009&lt;br /&gt;
* [http://www.nytimes.com/projects/magazine/ideas/2009/#m Massively Collaborative Mathematics], Jordan Ellenberg, The Ninth Annual Year in Ideas, New York Times, 2009.&lt;br /&gt;
* [http://www.hypios.com/thinking/2010/01/13/massively-collaborative-mathematics-lessons-from-polymath1/ Massively Collaborative Mathematics: lessons from polymath1], Hypios, Jan 13 2010&lt;br /&gt;
* [http://ths1104.wordpress.com/2010/02/13/open-reflexions-sur-fond-de-polymaths/ Open réflexions sur fond de Polymaths] (French), ths1104, Feb 13 2010&lt;br /&gt;
* [http://www.javiertordable.com/blog/2010/02/25/collaborative-mathematics-future-of-science Collaborative Mathematics and The Future of Science] Javier Tordable, February 26 2010&lt;br /&gt;
* [http://www.scientificamerican.com/article.cfm?id=problem-solved-tic-tac-toe-blog Problem Solved, LOL: A Complex Tic-Tac-Toe Puzzle Falls Thanks to Blog Comments] Davide Castelvecchi, Scientific American, March 17 2010&lt;br /&gt;
* [http://www.thebigquestions.com/2010/04/08/blogging-tic-tac-toe-and-the-future-of-math/ Blogging, Tic Tac Toe, and the Future of Math] Steve Landsburg, The Big Questions, April 4 2010&lt;br /&gt;
* [http://www.siam.org/news/news.php?issue=0043.03 Massively Collaborative Mathematics] Julie Rehmeyer, SIAM News, Volume 43(3), April 2010 (to appear)&lt;br /&gt;
* [http://mbarany.com/publications.html#WikiSymPolymath  `But this is blog maths and we&#039;re free to make up conventions as we go along&#039;: Polymath1 and the Modalities of `Massively Collaborative Mathematics.&#039;] Michael Barany,  Proceedings of the 6th International Symposium on Wikis and Open Collaboration, Gdansk, Poland, 2010.&lt;br /&gt;
* [http://www.cs.cmu.edu/~jcransh/papers/cranshaw_kittur.pdf J. Cranshaw and A. Kittur. The Polymath Project: Lessons from a successful online collaboration in mathematics]. In Proceedings of the Conference on Human Factors in Computing Systems, Vancouver, BC, Canada, May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028113.900-how-to-build-the-global-mathematics-brain.html How to build the global mathematics brain], Jacob Aron, New Scientist, 4 May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028112.900-mathematics-becomes-more-sociable.html Mathematics becomes more sociable], New Scientist, 5 May 2011.&lt;br /&gt;
* [http://polymathprojects.files.wordpress.com/2011/03/polymathias.jpg Mathematical Advances: Lone or Massively Collaborative Endeavors?] from IAS Institute Letter for fall 2010 based on a discussion organized by IAS fall 2010.&lt;br /&gt;
* [http://today.uconn.edu/blog/2010/10/will-crowdsourcing-revolutionize-scholarship Will ‘Crowdsourcing’ Revolutionize Scholarship?] An article in UConn Today by Jeremy Teitelbaum, Fall 2010.&lt;br /&gt;
* [http://online.wsj.com/article/SB10001424052970204644504576653573191370088.html The New Einsteins Will Be Scientists Who Share] The Wall street journal, October 2011.&lt;br /&gt;
* [http://www.nature.com/news/parallel-lines-1.14759?WT.ec_id=NATURE-20140227 Parallel lines], editorial, Nature 506, 407–408 (27 February 2014).&lt;br /&gt;
Additional links are very welcome.&lt;br /&gt;
&lt;br /&gt;
== Other links ==&lt;br /&gt;
&lt;br /&gt;
* [http://polymathprojects.org/ The polymath blog]&lt;br /&gt;
* [http://polymathprojects.org/general-polymath-rules/ General polymath rules]&lt;br /&gt;
&lt;br /&gt;
== Note on anonymous editing ==&lt;br /&gt;
&lt;br /&gt;
To help combat spam, anonymous editing has been disabled, and a captcha system added to hinder automated account creation. If this is causing problems, please email mn@michaelnielsen.org.&lt;br /&gt;
&lt;br /&gt;
== Note on image uploads ==&lt;br /&gt;
&lt;br /&gt;
Image uploads have been disabled, as they were causing problems with spam.  If you&#039;d like to upload an image, please email mn@michaelnielsen.org&lt;/div&gt;</summary>
		<author><name>Khare</name></author>
	</entry>
	<entry>
		<id>https://michaelnielsen.org/polymath/index.php?title=Main_Page&amp;diff=10944</id>
		<title>Main Page</title>
		<link rel="alternate" type="text/html" href="https://michaelnielsen.org/polymath/index.php?title=Main_Page&amp;diff=10944"/>
		<updated>2018-11-27T18:06:34Z</updated>

		<summary type="html">&lt;p&gt;Khare: /* Existing polymath projects */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{RightTOC}}&lt;br /&gt;
This is the wiki for &#039;&#039;polymath&#039;&#039; projects - massively collaborative online mathematical projects.  The idea of such projects originated in Tim Gowers&#039; blog post [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?]&lt;br /&gt;
&lt;br /&gt;
Many polymath projects will be proposed, planned, and run at [http://polymathprojects.org/ This Blog].&lt;br /&gt;
&lt;br /&gt;
A Polymath [[logo]] is being trialled.  If you have more suggestions, please add them to the [[logo]] page, or add to the discussion at [[Talk:logo]].&lt;br /&gt;
&lt;br /&gt;
The wiki is currently locked down due to a major influx of spam (July 29, 2013).  Please email mn@michaelnielsen.org if you&#039;d like an account set up, and I&#039;ll do my best to reply quickly. &lt;br /&gt;
&lt;br /&gt;
== Existing polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [[Polymath1]]: New proofs and bounds for the density Hales-Jewett theorem.  Initiated Feb 1, 2009; research results have now been published.&lt;br /&gt;
* [[Definable Banach Spaces|Polymath2]]: Must an “explicitly defined” Banach space contain &amp;lt;math&amp;gt;c_0&amp;lt;/math&amp;gt; or &amp;lt;math&amp;gt;l_p&amp;lt;/math&amp;gt;?  Initiated Feb 17, 2009; attempts to relaunch via wiki, June 9 2010.&lt;br /&gt;
* [[imo 2009 q6|Mini-polymath1]]: Solving Problem 6 of the 2009 International Mathematical Olympiad.  Initiated July 20, 2009; five proofs obtained so far.&lt;br /&gt;
* [[The polynomial Hirsch conjecture|Polymath3]].  The polynomial Hirsch conjecture.  Proposed July 17, 2009; launched, September 30, 2010.  &lt;br /&gt;
* [[finding primes|Polymath4]]: A deterministic way to find primes.  Proposed July 27, 2009; launched Aug 9, 2009.  Research results have now been published.&lt;br /&gt;
* [[The Erd&amp;amp;#337;s discrepancy problem|Polymath5]]: The Erd&amp;amp;#337;s discrepancy problem. Proposed Jan 10, 2010; launched Jan 19, 2010.  Activity ceased by the end of 2012, but results from the project were used to solve the problem in 2015.&lt;br /&gt;
* [[imo 2010|Mini-polymath2]]: Solving Problem 5 the 2010 International Mathematical Olympiad.  Proposed Jun 12, 2010; launched and solved, Jul 8 2010.&lt;br /&gt;
* [[Improving the bounds for Roth&#039;s theorem|Polymath6]]: Improving the bounds for Roth&#039;s theorem. Proposed Feb 5, 2011.&lt;br /&gt;
* [[imo 2011|Mini-polymath3]]: Solving a problem from the 2011 International Mathematical Olympiad.  Proposed Jun 9, 2011; launched and solved, Jul 19, 2011.&lt;br /&gt;
* [[imo 2012|Mini-polymath4]]: Solving a problem from the 2012 International Mathematical Olympiad.  Proposed, Jun 3, 2012; launched, July 12 2012.&lt;br /&gt;
* [[The hot spots conjecture|Polymath7]]:  Establishing the Hot Spots conjecture for acute-angled triangles.  Proposed, May 31st, 2012; launched, Jun 8, 2012.&lt;br /&gt;
* [[Bounded gaps between primes|Polymath8]]: Improving the bounds for small gaps between primes.  Proposed, June 4, 2013; launched, June 4, 2013.  Research results have now been published.&lt;br /&gt;
* [[Discretized Borel Determinacy and P=NP|Polymath9]]: exploring Borel determinacy-based methods for giving complexity bounds.  Proposed, Oct 24, 2013; launched, Nov 3, 2013.&lt;br /&gt;
* [[The Erdos-Rado sunflower lemma|Polymath10]]: improving the bounds for the Erdos-Rado sunflower lemma.  Launched, Nov 2, 2015.&lt;br /&gt;
* [[Frankl&#039;s union-closed conjecture|Polymath11]]: proving Frankl&#039;s union-closed conjecture. Proposed Jan 21, 2016; launched Jan 29, 2016.  Concluded, Jan 17, 2017.&lt;br /&gt;
* [[Rota&#039;s conjecture|Polymath12]]: proving Rota&#039;s conjecture.  Proposed Feb 28, 2017.&lt;br /&gt;
* [[Intransitive dice|Polymath13]]: Intransitive dice.  Proposed Apr 28, 2017.&lt;br /&gt;
* [[linear norm|Polymath14]]: Classifying homogeneous norms on groups.  Initiated Dec 16, 2017; solved Dec 21, 2017.  Research results have now been published.&lt;br /&gt;
* [[De_Bruijn-Newman constant|Polymath15]]: Upper bounding the de Bruin-Newman constant.  Proposed, Jan 24 2018; launched Jan 27 2018.&lt;br /&gt;
* [[Hadwiger-Nelson problem|Polymath16]]: Simplifying the lower bound proof for the Hadwiger-Nelson problem.  Proposed, Apr 10, 2018; launched, Apr 14, 2018.&lt;br /&gt;
&lt;br /&gt;
== Polymath-like projects ==&lt;br /&gt;
&lt;br /&gt;
* Scott Aaronson&#039;s &amp;quot;philomath project&amp;quot;: &amp;quot;[http://scottaaronson.com/blog/?p=453 Sensitivity vs. Block sensitivity]&amp;quot; (see also [http://mathoverflow.net/questions/31482/the-sensitivity-of-2-colorings-of-the-d-dimensional-integer-lattice this Math Overflow question]).  Launched Jul 13, 2010.&lt;br /&gt;
* A wiki page clearinghouse for the [[Deolalikar P vs NP paper]].  Launched Aug 10, 2010.&lt;br /&gt;
* &amp;lt;del&amp;gt;[http://researchtrends.wikia.com/wiki/Main_Page Math Research Trends Wiki] &amp;quot;research in the middle&amp;quot;&amp;lt;/del&amp;gt; This project is recommended to be discontinued in favor of &amp;lt;b&amp;gt;[https://conference.portonvictor.org/wiki/Research_in_the_middle Research in the middle project] at [https://conference.portonvictor.org Virtual scientific conference]&amp;lt;/b&amp;gt;.&lt;br /&gt;
* The page for the [[ABC conjecture]] contains links and information about Mochizuki&#039;s claimed proof of this conjecture.&lt;br /&gt;
&lt;br /&gt;
== Proposed polymath projects ==&lt;br /&gt;
&lt;br /&gt;
* [http://gilkalai.wordpress.com/2009/03/25/an-open-discussion-and-polls-around-roths-theorem/ The cap set problem].  Proposed March 25, 2009 (see also these [http://gilkalai.wordpress.com/2009/05/11/around-the-cap-set-problem-b/ two] [http://gilkalai.wordpress.com/2009/05/18/the-cap-set-problem-and-frankl-rodl-theorem-c/ followup] posts).&lt;br /&gt;
* [[Boshernitzan’s problem]].  Proposed July 27, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/09/16/possible-future-polymath-projects/ Possible future polymath projects].  Discussion opened September 16, 2009.&lt;br /&gt;
* [http://rjlipton.wordpress.com/2011/05/12/a-possible-polymath-project/ A possible polymath project:] Proposal by Richard Lipton to attack a conjecture due to Erdos, about a class of Diophantine equations.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
A (partial) list of proposed projects can be found [http://polymathprojects.org/category/polymath-proposals/ here].&lt;br /&gt;
&lt;br /&gt;
If you have a tentative proposal for a polymath project, you can either make a post on it on your own blog, or place it [[other proposed projects|here]].&lt;br /&gt;
&lt;br /&gt;
== Discussions about polymath ==&lt;br /&gt;
&lt;br /&gt;
* [http://gowers.wordpress.com/2009/01/27/is-massively-collaborative-mathematics-possible/ Is massively collaborative mathematics possible?] Tim Gowers, January 27, 2009.&lt;br /&gt;
* [http://lucatrevisan.wordpress.com/2009/02/01/a-peoples-history-of-mathematics/ A people&#039;s history of mathematics] Luca Trevisan, February 1, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=553 The polymath project] Michael Nielsen, February 3, 2009.&lt;br /&gt;
* [http://www.neverendingbooks.org/index.php/yet-another-math20-proposal.html Yet another math 2.0 proposal] Lieven le Bruyn, February 11, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/10/polymath1-and-open-collaborative-mathematics/ Polymath1 and open collaborative mathematics] Tim Gowers, March 10, 2009.&lt;br /&gt;
* [http://maxwelldemon.com/2009/03/14/polymath/ Polymath] Edmund Harriss, March 14, 2009.&lt;br /&gt;
* [http://science.slashdot.org/article.pl?sid=09/03/18/194228 Massive open collaboration in mathematics declared a success] Slashdot, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=581 How changing the technology of collaboration can change the nature of collaboration] Michael Nielsen, March 18, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/?p=584 The polymath project: scope of participation] Michael Nielsen, March 20, 2009.&lt;br /&gt;
* [http://gowers.wordpress.com/2009/03/24/can-polymath-be-scaled-up/ Can polymath be scaled up?] Tim Gowers, March 24, 2009.&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/03/24/concluding-notes-on-the-polymath-project-and-a-challenge/ Concluding notes on the polymath project - and a challenge] Vilpulniak, March 24, 2009.&lt;br /&gt;
* [http://michaelnielsen.org/blog/on-scaling-up-the-polymath-project/ On scaling up the polymath project] Michael Nielsen, March 25, 2009.&lt;br /&gt;
* [http://numberwarrior.wordpress.com/2009/03/25/a-gentle-introduction-to-the-polymath-project/ A gentle introduction to the polymath project] Jason Dyer, March 25, 2009.&lt;br /&gt;
* [http://blogs.telegraph.co.uk/technology/iandouglas/9656357/tim_gowers_and_the_polymaths/ Tim Gowers and the polymaths] Ian Douglas (the Telegraph), April 29, 2009&lt;br /&gt;
* [http://terrytao.wordpress.com/2009/07/22/imo-2009-q6-mini-polymath-project-impressions-reflections-analysis/ IMO 2009 Q6 as mini-polymath project: impressions, reflections, analysis] Terence Tao, July 22, 2009.&lt;br /&gt;
* [http://polymathprojects.org/2009/07/27/selecting-the-next-polymath-project/ Selecting the next polymath project] Terence Tao, July 27, 2009.&lt;br /&gt;
* [http://blog.jonudell.net/2009/07/31/polymath-equals-user-innovatio/ Polymath equals user innovation] Jon Udell, July 31, 2009.&lt;br /&gt;
* [http://scienceblogs.com/christinaslisrant/2009/08/an_overview_of_the_polymath_pr.php An overview of the polymath project] Christina Pikas, August 1, 2009 &lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/08/09/collaborative-mathematics-etc/ Collaborative mathematics etc.] Vipulniak, August 9, 2009&lt;br /&gt;
* [http://www.nature.com/nature/journal/v461/n7266/full/461879a.html Massively collaborative mathematics] Tim Gowers, Michael Nielsen, Nature, October 15, 2009&lt;br /&gt;
* [http://portonmath.wordpress.com/2009/10/25/collaborative-research-of-filters/ Collaborative math research – a real example] Victor Porton, October 24, 2009&lt;br /&gt;
* [http://whatisresearch.wordpress.com/2009/10/26/polymath-again/ Polymath again] Vipulniak, October 26, 2009&lt;br /&gt;
* [http://www.kennislink.nl/publicaties/wiskunde-met-zijn-allen Wiskunde met zijn allen] (Dutch), Alex van den Brandhof, Kennislink, November 12, 2009&lt;br /&gt;
* [http://www.sciencenews.org/view/generic/id/50532/title/Mathematics_by_collaboration Mathematics by collaboration], Julie Rehmeyer, ScienceNews, December 8, 2009&lt;br /&gt;
* [http://www.nytimes.com/projects/magazine/ideas/2009/#m Massively Collaborative Mathematics], Jordan Ellenberg, The Ninth Annual Year in Ideas, New York Times, 2009.&lt;br /&gt;
* [http://www.hypios.com/thinking/2010/01/13/massively-collaborative-mathematics-lessons-from-polymath1/ Massively Collaborative Mathematics: lessons from polymath1], Hypios, Jan 13 2010&lt;br /&gt;
* [http://ths1104.wordpress.com/2010/02/13/open-reflexions-sur-fond-de-polymaths/ Open réflexions sur fond de Polymaths] (French), ths1104, Feb 13 2010&lt;br /&gt;
* [http://www.javiertordable.com/blog/2010/02/25/collaborative-mathematics-future-of-science Collaborative Mathematics and The Future of Science] Javier Tordable, February 26 2010&lt;br /&gt;
* [http://www.scientificamerican.com/article.cfm?id=problem-solved-tic-tac-toe-blog Problem Solved, LOL: A Complex Tic-Tac-Toe Puzzle Falls Thanks to Blog Comments] Davide Castelvecchi, Scientific American, March 17 2010&lt;br /&gt;
* [http://www.thebigquestions.com/2010/04/08/blogging-tic-tac-toe-and-the-future-of-math/ Blogging, Tic Tac Toe, and the Future of Math] Steve Landsburg, The Big Questions, April 4 2010&lt;br /&gt;
* [http://www.siam.org/news/news.php?issue=0043.03 Massively Collaborative Mathematics] Julie Rehmeyer, SIAM News, Volume 43(3), April 2010 (to appear)&lt;br /&gt;
* [http://mbarany.com/publications.html#WikiSymPolymath  `But this is blog maths and we&#039;re free to make up conventions as we go along&#039;: Polymath1 and the Modalities of `Massively Collaborative Mathematics.&#039;] Michael Barany,  Proceedings of the 6th International Symposium on Wikis and Open Collaboration, Gdansk, Poland, 2010.&lt;br /&gt;
* [http://www.cs.cmu.edu/~jcransh/papers/cranshaw_kittur.pdf J. Cranshaw and A. Kittur. The Polymath Project: Lessons from a successful online collaboration in mathematics]. In Proceedings of the Conference on Human Factors in Computing Systems, Vancouver, BC, Canada, May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028113.900-how-to-build-the-global-mathematics-brain.html How to build the global mathematics brain], Jacob Aron, New Scientist, 4 May 2011.&lt;br /&gt;
* [http://www.newscientist.com/article/mg21028112.900-mathematics-becomes-more-sociable.html Mathematics becomes more sociable], New Scientist, 5 May 2011.&lt;br /&gt;
* [http://polymathprojects.files.wordpress.com/2011/03/polymathias.jpg Mathematical Advances: Lone or Massively Collaborative Endeavors?] from IAS Institute Letter for fall 2010 based on a discussion organized by IAS fall 2010.&lt;br /&gt;
* [http://today.uconn.edu/blog/2010/10/will-crowdsourcing-revolutionize-scholarship Will ‘Crowdsourcing’ Revolutionize Scholarship?] An article in UConn Today by Jeremy Teitelbaum, Fall 2010.&lt;br /&gt;
* [http://online.wsj.com/article/SB10001424052970204644504576653573191370088.html The New Einsteins Will Be Scientists Who Share] The Wall street journal, October 2011.&lt;br /&gt;
* [http://www.nature.com/news/parallel-lines-1.14759?WT.ec_id=NATURE-20140227 Parallel lines], editorial, Nature 506, 407–408 (27 February 2014).&lt;br /&gt;
Additional links are very welcome.&lt;br /&gt;
&lt;br /&gt;
== Other links ==&lt;br /&gt;
&lt;br /&gt;
* [http://polymathprojects.org/ The polymath blog]&lt;br /&gt;
* [http://polymathprojects.org/general-polymath-rules/ General polymath rules]&lt;br /&gt;
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To help combat spam, anonymous editing has been disabled, and a captcha system added to hinder automated account creation. If this is causing problems, please email mn@michaelnielsen.org.&lt;br /&gt;
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== Note on image uploads ==&lt;br /&gt;
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		<author><name>Khare</name></author>
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