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	<id>https://michaelnielsen.org/polymath/api.php?action=feedcontributions&amp;feedformat=atom&amp;user=Pace</id>
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	<link rel="self" type="application/atom+xml" href="https://michaelnielsen.org/polymath/api.php?action=feedcontributions&amp;feedformat=atom&amp;user=Pace"/>
	<link rel="alternate" type="text/html" href="https://michaelnielsen.org/polymath/index.php?title=Special:Contributions/Pace"/>
	<updated>2026-04-07T10:49:59Z</updated>
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	<entry>
		<id>https://michaelnielsen.org/polymath/index.php?title=Dickson-Hardy-Littlewood_theorems&amp;diff=8260</id>
		<title>Dickson-Hardy-Littlewood theorems</title>
		<link rel="alternate" type="text/html" href="https://michaelnielsen.org/polymath/index.php?title=Dickson-Hardy-Littlewood_theorems&amp;diff=8260"/>
		<updated>2013-07-01T20:25:03Z</updated>

		<summary type="html">&lt;p&gt;Pace: Added a 2 to an exponent on a j.&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;For any integer &amp;lt;math&amp;gt;k_0 \geq 2&amp;lt;/math&amp;gt;, let &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; denote the assertion that given any admissible &amp;lt;math&amp;gt;k_0&amp;lt;/math&amp;gt;-tuple &amp;lt;math&amp;gt;{\mathcal H}&amp;lt;/math&amp;gt;, that infinitely many translates of &amp;lt;math&amp;gt;{\mathcal H}&amp;lt;/math&amp;gt; contain at least two primes.  Thus for instance &amp;lt;math&amp;gt;DHL[2,2]&amp;lt;/math&amp;gt; would imply the twin prime conjecture.  The acronym DHL stands for &amp;quot;Dickson-Hardy-Littlewood&amp;quot;, and originates from [http://arxiv.org/abs/1305.6289 this paper of Pintz].&lt;br /&gt;
&lt;br /&gt;
It is known how to deduce results &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; from three classes of estimates:&lt;br /&gt;
&lt;br /&gt;
* Elliott-Halberstam estimates &amp;lt;math&amp;gt;EH[\theta]&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;1/2 &amp;lt; \theta &amp;lt; 1&amp;lt;/math&amp;gt;.&lt;br /&gt;
* Motohashi-Pintz-Zhang estimates &amp;lt;math&amp;gt;MPZ[\varpi,\delta]&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;0 &amp;lt; \varpi &amp;lt; 1/4&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;0 &amp;lt; \delta &amp;lt; 1/4+\varpi&amp;lt;/math&amp;gt;.&lt;br /&gt;
* Motohashi-Pintz-Zhang estimates &amp;lt;math&amp;gt;MPZ&#039;[\varpi,\delta]&amp;lt;/math&amp;gt; for densely divisible moduli for some &amp;lt;math&amp;gt;0 &amp;lt; \varpi &amp;lt; 1/4&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;0 &amp;lt; \delta &amp;lt; 1/4+\varpi&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The Elliott-Halberstam estimates are the simplest to use, but unfortunately no estimate of the form &amp;lt;math&amp;gt;EH[\theta]&amp;lt;/math&amp;gt; for nay &amp;lt;math&amp;gt;\theta &amp;gt; 1/2&amp;lt;/math&amp;gt; is known unconditionally at present.  Zhang was the first to establish a result of the form &amp;lt;math&amp;gt;MPZ[\varpi,\theta]&amp;lt;/math&amp;gt;, which is weaker than &amp;lt;math&amp;gt;EH[1/2+2\varpi+]&amp;lt;/math&amp;gt;, for some &amp;lt;math&amp;gt;\varpi,\theta&amp;gt;0&amp;lt;/math&amp;gt;.  More recently, we have switched to using &amp;lt;math&amp;gt;MPZ&#039;[\varpi,\theta]&amp;lt;/math&amp;gt;, an estimate of intermediate strength between &amp;lt;math&amp;gt;MPZ[\varpi,\delta]&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;EH[1/2+2\varpi+]&amp;lt;/math&amp;gt;, as the conversion of this estimate to a &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; result is more efficient in the &amp;lt;math&amp;gt;\delta&amp;lt;/math&amp;gt; parameter.  The precise definition of the MPZ and MPZ&#039; estimates can be found at the page on [[distribution of primes in smooth moduli]].&lt;br /&gt;
&lt;br /&gt;
== Converting EH to DHL ==&lt;br /&gt;
&lt;br /&gt;
In the [http://www.ams.org/mathscinet-getitem?mr=2552109 breakthrough paper of Goldston, Pintz, and Yildirim], it was shown that &amp;lt;math&amp;gt;EH[\theta]&amp;lt;/math&amp;gt; implied &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; whenever&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;2\theta &amp;gt; (1 + \frac{1}{2l_0+1}) (1 + \frac{2l_0+1}{k_0})&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
for some positive integer &amp;lt;math&amp;gt;l_0&amp;lt;/math&amp;gt;.  Actually (as noted [http://terrytao.wordpress.com/2013/06/03/the-prime-tuples-conjecture-sieve-theory-and-the-work-of-goldston-pintz-yildirim-motohashi-pintz-and-zhang/ here]), there is nothing preventing the argument for working for non-integer &amp;lt;math&amp;gt;l_0 &amp;gt; 0&amp;lt;/math&amp;gt; as well, so we can optimise this condition as&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;2\theta &amp;gt; (1 + \frac{1}{\sqrt{k_0}})^2&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Some further optimisation of this condition was performed in the paper of Goldston, Pintz, and Yildirim by working with general polynomial weights rather than monomial weights.  In [http://www.renyi.hu/~revesz/ThreeCorr0grey.pdf this paper of Farkas, Pintz, and Revesz], the optimal weight was found (coming from a Bessel function), and the optimised condition&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;2\theta &amp;gt; \frac{j_{k_0-2}^2}{k_0(k_0-1)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
was obtained, where &amp;lt;math&amp;gt;j_{k_0-2}=j_{k_0-2,1}&amp;lt;/math&amp;gt; is the first positive zero of the Bessel function &amp;lt;math&amp;gt;J_{k_0-2}&amp;lt;/math&amp;gt;.  See for instance [http://terrytao.wordpress.com/2013/06/03/the-prime-tuples-conjecture-sieve-theory-and-the-work-of-goldston-pintz-yildirim-motohashi-pintz-and-zhang/ this post] for details.&lt;br /&gt;
&lt;br /&gt;
== Converting MPZ to DHL ==&lt;br /&gt;
&lt;br /&gt;
The observation that &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; could be deduced from &amp;lt;math&amp;gt;MPZ[\varpi,\delta]&amp;lt;/math&amp;gt; if &amp;lt;math&amp;gt;k_0&amp;lt;/math&amp;gt; was sufficiently large depending on &amp;lt;math&amp;gt;\varpi,\delta&amp;lt;/math&amp;gt; was first made in the literature [http://www.ams.org/mathscinet-getitem?mr=2414788 by Motohashi and Pintz].  In the [http://annals.math.princeton.edu/wp-content/uploads/YitangZhang.pdf paper of Zhang], an explicit implication was established: &amp;lt;math&amp;gt;MPZ[\varpi,\varpi]&amp;lt;/math&amp;gt; implies &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; whenever there exists an integer &amp;lt;math&amp;gt;l_0&amp;gt;0&amp;lt;/math&amp;gt; such that&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) (1-\kappa_2) &amp;gt; (1 + \frac{1}{2l_0+1}) (1 + \frac{2l_0+1}{k_0}) (1 + \kappa_1)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_1 := \delta_1( 1 + \delta_2^2 + k_0 \log(1+\frac{1}{4\varpi}) \binom{k_0+2l_0}{k_0}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_2 := \delta_1 (1+4\varpi) ( 1 + \delta_2^2 + k_0 \log(1+\frac{1}{4\varpi}) \binom{k_0+2l_0+1}{k_0-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \delta_1 := (1+4\varpi)^{-k_0}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \delta_2 := \sum_{0 \leq j &amp;lt; 1+\frac{1}{4\varpi}} \frac{ \log(1+\frac{1}{4\varpi}) k_0)^j}{j!}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;\delta_2&amp;lt;/math&amp;gt; was lowered to &amp;lt;math&amp;gt;\prod_{0 \leq j &amp;lt; 1+\frac{1}{4\varpi}} (1 + k_0 \log(1+\frac{1}{j})&amp;lt;/math&amp;gt; in [http://terrytao.files.wordpress.com/2013/05/bounds.pdf these notes].  Subsequently, the values of &amp;lt;math&amp;gt;\kappa_1,\kappa_2&amp;lt;/math&amp;gt; were improved to&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_1 := (\delta_1 + \sum_{j=1}^{1/4\varpi} \delta_1^j \delta_{2,j}^2 + \delta_1 k_0 \log(1+\frac{1}{4\varpi})) \binom{k_0+2l_0}{k_0}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_2 := (\delta_1 (1+4\varpi) + \sum_{j=1}^{1/4\varpi} \delta_1^j (1+4\varpi)^j \delta_{2,j}^2 + \delta_1 (1+4\varpi) k_0 \log(1+\frac{1}{4\varpi}) \binom{k_0+2l_0+1}{k_0-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \delta_{2,j} := \prod_{i=1}^j (1 + k_0 \log(1+\frac{1}{i}) )&amp;lt;/math&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
again, see [http://terrytao.files.wordpress.com/2013/05/bounds.pdf these notes].   As before, &amp;lt;math&amp;gt;l_0&amp;lt;/math&amp;gt; can be taken to be non-integer.&lt;br /&gt;
&lt;br /&gt;
The constraint was then [http://terrytao.wordpress.com/2013/06/03/the-prime-tuples-conjecture-sieve-theory-and-the-work-of-goldston-pintz-yildirim-motohashi-pintz-and-zhang/ improved further in this post] to deduce &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; from &amp;lt;math&amp;gt;MPZ[\varpi,\delta]&amp;lt;/math&amp;gt; whenever&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) &amp;gt; (1 + \frac{1}{2l_0+1}) (1 + \frac{2l_0+1}{k_0}) (1 + \kappa)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa = \sum_{1 \leq n \leq \frac{1+4\varpi}{2\delta}} (1 - \frac{2n\delta}{1+4\varpi})^{k_0/2+l_0} \prod_{j=1}^n (1+3k_0 \log(1+\frac{1}{j}))&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Using the optimal Bessel weight, this condition was improved to&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) &amp;gt; \frac{j^{2}_{k_0-2}}{k_0(k_0-1)} (1 + \kappa)&amp;lt;/math&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
again, see [http://terrytao.wordpress.com/2013/06/03/the-prime-tuples-conjecture-sieve-theory-and-the-work-of-goldston-pintz-yildirim-motohashi-pintz-and-zhang/ this post].&lt;br /&gt;
&lt;br /&gt;
A variant of this criterion was developed using the elementary Selberg sieve in [http://terrytao.wordpress.com/2013/06/08/the-elementary-selberg-sieve-and-bounded-prime-gaps/ this post], but never used.  A subsequent refined criterion was established in [http://terrytao.wordpress.com/2013/06/11/further-analysis-of-the-truncated-gpy-sieve/ this post], namely that&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) (1-\kappa&#039;) &amp;gt; \frac{j^{2}_{k_0-2}}{k_0(k_0-1)} (1 + \kappa)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa := \sum_{1 \leq n &amp;lt; \frac{1+4\varpi}{2\delta}} \frac{3^n+1}{2} \frac{k_0^n}{n!} (\int_{4\delta/(1+\varpi)}^1 (1-t)^{k_0/2} \frac{dt}{t})^n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa&#039; := \sum_{2 \leq n &amp;lt; \frac{1+4\varpi}{2\delta}} \frac{3^n-1}{2} \frac{(k_0-1)^n}{n!} (\int_{4\delta/(1+\varpi)}^1 (1-t)^{(k_0-1)/2} \frac{dt}{t})^n.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slight refinement in [http://terrytao.wordpress.com/2013/06/11/further-analysis-of-the-truncated-gpy-sieve/#comment-234845 this comment] allows the condition &amp;lt;math&amp;gt;n \geq 2&amp;lt;/math&amp;gt; in the definition of &amp;lt;math&amp;gt;\kappa&#039;&amp;lt;/math&amp;gt; to be raised to &amp;lt;math&amp;gt;n \geq 3&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
An [http://terrytao.wordpress.com/2013/06/18/a-truncated-elementary-selberg-sieve-of-pintz argument of Pintz] yields the following improved values of &amp;lt;math&amp;gt;\kappa,\kappa&#039;&amp;lt;/math&amp;gt; in the above criterion:&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa := 0 &amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa&#039; := 2 \kappa_1 + 2 \kappa_2&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_1 := \int_{4\delta/(1+4\varpi)}^1 (1-t)^{(k_0-1)/2} \frac{dt}{t}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_2 := (k_0-1) \int_{4\delta/(1+4\varpi)}^1 (1-t)^{k_0-1} \frac{dt}{t}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
== Converting MPZ&#039; to DHL ==&lt;br /&gt;
&lt;br /&gt;
An efficient [http://terrytao.wordpress.com/2013/06/18/a-truncated-elementary-selberg-sieve-of-pintz argument of Pintz], based on the elementary Selberg sieve, allows one to deduce &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; from &amp;lt;math&amp;gt;MPZ&#039;[\varpi,\delta]&amp;lt;/math&amp;gt; with almost no loss with respect to the &amp;lt;math&amp;gt;\delta&amp;lt;/math&amp;gt; parameter.  As currently optimised, the criterion takes the form&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) (1-2\kappa_1 - 2\kappa_2 - 2\kappa_3) &amp;gt; \frac{j^{2}_{k_0-2}}{k_0(k_0-1)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_1 := \int_{\theta}^1 (1-t)^{(k_0-1)/2} \frac{dt}{t}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_2 := (k_0-1) \int_{\theta}^1 (1-t)^{k_0-1} \frac{dt}{t}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_3 := \tilde \theta \frac{J_{k_0-2}(\sqrt{\tilde \theta} j_{k_0-2})^2 - J_{k_0-3}(\sqrt{\tilde \theta} j_{k_0-2}) J_{k_0-1}(\sqrt{\tilde \theta} j_{k_0-2})}{ J_{k_0-3}(j_{k_0-2})^2 } &lt;br /&gt;
\exp( A + (k_0-1) \int_{\tilde \delta}^\theta e^{-(A+2\alpha)t} \frac{dt}{t} )&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \alpha := \frac{j_{k_0-2}^2}{4(k_0-1)}&amp;lt;/math&amp;gt;&lt;br /&gt;
:&amp;lt;math&amp;gt; \theta := \frac{\delta&#039;}{1/4 + \varpi}&amp;lt;/math&amp;gt;&lt;br /&gt;
:&amp;lt;math&amp;gt; \tilde \theta := \frac{(\delta&#039; - \delta)/2 + \varpi}{1/4 + \varpi}&amp;lt;/math&amp;gt;&lt;br /&gt;
:&amp;lt;math&amp;gt; \tilde \delta := \frac{\delta}{1/4 + \varpi}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
and &amp;lt;math&amp;gt;A&amp;gt;0&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\delta \leq \delta&#039; \leq \frac{1}{4} + \varpi&amp;lt;/math&amp;gt; are parameters one is free to optimise over.&lt;br /&gt;
&lt;br /&gt;
Here is some simple Maple code to verify the above criterion for given choices of &amp;lt;math&amp;gt;k_0,\varpi,\delta,\delta&#039;,A&amp;lt;/math&amp;gt;:&lt;br /&gt;
&lt;br /&gt;
 k0 := [INSERT VALUE HERE];&lt;br /&gt;
 varpi := [INSERT VALUE HERE];&lt;br /&gt;
 delta := [INSERT VALUE HERE];&lt;br /&gt;
 deltap := [INSERT VALUE HERE]; &lt;br /&gt;
 A := [INSERT VALUE HERE];&lt;br /&gt;
 theta := deltap / (1/4 + varpi);&lt;br /&gt;
 thetat := ((deltap - delta)/2 + varpi) / (1/4 + varpi);&lt;br /&gt;
 deltat := delta / (1/4 + varpi);&lt;br /&gt;
 j := BesselJZeros(k0-2,1);&lt;br /&gt;
 eps := 1 - j^2 / (k0 * (k0-1) * (1+4*varpi));&lt;br /&gt;
 kappa1 := int( (1-t)^((k0-1)/2)/t, t = theta..1, numeric);&lt;br /&gt;
 kappa2 := (k0-1) * int( (1-t)^(k0-1)/t, t=theta..1, numeric);&lt;br /&gt;
 alpha := j^2 / (4 * (k0-1));&lt;br /&gt;
 e := exp( A + (k0-1) * int( exp(-(A+2*alpha)*t)/t, t=deltat..theta, numeric ) );&lt;br /&gt;
 gd := (j^2/2) * BesselJ(k0-3,j)^2;&lt;br /&gt;
 tn := sqrt(thetat)*j;&lt;br /&gt;
 gn := (tn^2/2) * (BesselJ(k0-2,tn)^2 - BesselJ(k0-3,tn)*BesselJ(k0-1,tn));&lt;br /&gt;
 kappa3 := (gn/gd) * e;&lt;br /&gt;
 eps2 := 2*(kappa1+kappa2+kappa3);&lt;br /&gt;
 # we win if eps2 &amp;lt; eps&lt;/div&gt;</summary>
		<author><name>Pace</name></author>
	</entry>
	<entry>
		<id>https://michaelnielsen.org/polymath/index.php?title=Dickson-Hardy-Littlewood_theorems&amp;diff=8259</id>
		<title>Dickson-Hardy-Littlewood theorems</title>
		<link rel="alternate" type="text/html" href="https://michaelnielsen.org/polymath/index.php?title=Dickson-Hardy-Littlewood_theorems&amp;diff=8259"/>
		<updated>2013-07-01T20:24:14Z</updated>

		<summary type="html">&lt;p&gt;Pace: /* Converting MPZ to DHL */  Added the exponent 2 to some of the j&amp;#039;s&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;For any integer &amp;lt;math&amp;gt;k_0 \geq 2&amp;lt;/math&amp;gt;, let &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; denote the assertion that given any admissible &amp;lt;math&amp;gt;k_0&amp;lt;/math&amp;gt;-tuple &amp;lt;math&amp;gt;{\mathcal H}&amp;lt;/math&amp;gt;, that infinitely many translates of &amp;lt;math&amp;gt;{\mathcal H}&amp;lt;/math&amp;gt; contain at least two primes.  Thus for instance &amp;lt;math&amp;gt;DHL[2,2]&amp;lt;/math&amp;gt; would imply the twin prime conjecture.  The acronym DHL stands for &amp;quot;Dickson-Hardy-Littlewood&amp;quot;, and originates from [http://arxiv.org/abs/1305.6289 this paper of Pintz].&lt;br /&gt;
&lt;br /&gt;
It is known how to deduce results &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; from three classes of estimates:&lt;br /&gt;
&lt;br /&gt;
* Elliott-Halberstam estimates &amp;lt;math&amp;gt;EH[\theta]&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;1/2 &amp;lt; \theta &amp;lt; 1&amp;lt;/math&amp;gt;.&lt;br /&gt;
* Motohashi-Pintz-Zhang estimates &amp;lt;math&amp;gt;MPZ[\varpi,\delta]&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;0 &amp;lt; \varpi &amp;lt; 1/4&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;0 &amp;lt; \delta &amp;lt; 1/4+\varpi&amp;lt;/math&amp;gt;.&lt;br /&gt;
* Motohashi-Pintz-Zhang estimates &amp;lt;math&amp;gt;MPZ&#039;[\varpi,\delta]&amp;lt;/math&amp;gt; for densely divisible moduli for some &amp;lt;math&amp;gt;0 &amp;lt; \varpi &amp;lt; 1/4&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;0 &amp;lt; \delta &amp;lt; 1/4+\varpi&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The Elliott-Halberstam estimates are the simplest to use, but unfortunately no estimate of the form &amp;lt;math&amp;gt;EH[\theta]&amp;lt;/math&amp;gt; for nay &amp;lt;math&amp;gt;\theta &amp;gt; 1/2&amp;lt;/math&amp;gt; is known unconditionally at present.  Zhang was the first to establish a result of the form &amp;lt;math&amp;gt;MPZ[\varpi,\theta]&amp;lt;/math&amp;gt;, which is weaker than &amp;lt;math&amp;gt;EH[1/2+2\varpi+]&amp;lt;/math&amp;gt;, for some &amp;lt;math&amp;gt;\varpi,\theta&amp;gt;0&amp;lt;/math&amp;gt;.  More recently, we have switched to using &amp;lt;math&amp;gt;MPZ&#039;[\varpi,\theta]&amp;lt;/math&amp;gt;, an estimate of intermediate strength between &amp;lt;math&amp;gt;MPZ[\varpi,\delta]&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;EH[1/2+2\varpi+]&amp;lt;/math&amp;gt;, as the conversion of this estimate to a &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; result is more efficient in the &amp;lt;math&amp;gt;\delta&amp;lt;/math&amp;gt; parameter.  The precise definition of the MPZ and MPZ&#039; estimates can be found at the page on [[distribution of primes in smooth moduli]].&lt;br /&gt;
&lt;br /&gt;
== Converting EH to DHL ==&lt;br /&gt;
&lt;br /&gt;
In the [http://www.ams.org/mathscinet-getitem?mr=2552109 breakthrough paper of Goldston, Pintz, and Yildirim], it was shown that &amp;lt;math&amp;gt;EH[\theta]&amp;lt;/math&amp;gt; implied &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; whenever&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;2\theta &amp;gt; (1 + \frac{1}{2l_0+1}) (1 + \frac{2l_0+1}{k_0})&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
for some positive integer &amp;lt;math&amp;gt;l_0&amp;lt;/math&amp;gt;.  Actually (as noted [http://terrytao.wordpress.com/2013/06/03/the-prime-tuples-conjecture-sieve-theory-and-the-work-of-goldston-pintz-yildirim-motohashi-pintz-and-zhang/ here]), there is nothing preventing the argument for working for non-integer &amp;lt;math&amp;gt;l_0 &amp;gt; 0&amp;lt;/math&amp;gt; as well, so we can optimise this condition as&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;2\theta &amp;gt; (1 + \frac{1}{\sqrt{k_0}})^2&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Some further optimisation of this condition was performed in the paper of Goldston, Pintz, and Yildirim by working with general polynomial weights rather than monomial weights.  In [http://www.renyi.hu/~revesz/ThreeCorr0grey.pdf this paper of Farkas, Pintz, and Revesz], the optimal weight was found (coming from a Bessel function), and the optimised condition&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;2\theta &amp;gt; \frac{j_{k_0-2}^2}{k_0(k_0-1)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
was obtained, where &amp;lt;math&amp;gt;j_{k_0-2}=j_{k_0-2,1}&amp;lt;/math&amp;gt; is the first positive zero of the Bessel function &amp;lt;math&amp;gt;J_{k_0-2}&amp;lt;/math&amp;gt;.  See for instance [http://terrytao.wordpress.com/2013/06/03/the-prime-tuples-conjecture-sieve-theory-and-the-work-of-goldston-pintz-yildirim-motohashi-pintz-and-zhang/ this post] for details.&lt;br /&gt;
&lt;br /&gt;
== Converting MPZ to DHL ==&lt;br /&gt;
&lt;br /&gt;
The observation that &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; could be deduced from &amp;lt;math&amp;gt;MPZ[\varpi,\delta]&amp;lt;/math&amp;gt; if &amp;lt;math&amp;gt;k_0&amp;lt;/math&amp;gt; was sufficiently large depending on &amp;lt;math&amp;gt;\varpi,\delta&amp;lt;/math&amp;gt; was first made in the literature [http://www.ams.org/mathscinet-getitem?mr=2414788 by Motohashi and Pintz].  In the [http://annals.math.princeton.edu/wp-content/uploads/YitangZhang.pdf paper of Zhang], an explicit implication was established: &amp;lt;math&amp;gt;MPZ[\varpi,\varpi]&amp;lt;/math&amp;gt; implies &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; whenever there exists an integer &amp;lt;math&amp;gt;l_0&amp;gt;0&amp;lt;/math&amp;gt; such that&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) (1-\kappa_2) &amp;gt; (1 + \frac{1}{2l_0+1}) (1 + \frac{2l_0+1}{k_0}) (1 + \kappa_1)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_1 := \delta_1( 1 + \delta_2^2 + k_0 \log(1+\frac{1}{4\varpi}) \binom{k_0+2l_0}{k_0}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_2 := \delta_1 (1+4\varpi) ( 1 + \delta_2^2 + k_0 \log(1+\frac{1}{4\varpi}) \binom{k_0+2l_0+1}{k_0-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \delta_1 := (1+4\varpi)^{-k_0}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \delta_2 := \sum_{0 \leq j &amp;lt; 1+\frac{1}{4\varpi}} \frac{ \log(1+\frac{1}{4\varpi}) k_0)^j}{j!}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;\delta_2&amp;lt;/math&amp;gt; was lowered to &amp;lt;math&amp;gt;\prod_{0 \leq j &amp;lt; 1+\frac{1}{4\varpi}} (1 + k_0 \log(1+\frac{1}{j})&amp;lt;/math&amp;gt; in [http://terrytao.files.wordpress.com/2013/05/bounds.pdf these notes].  Subsequently, the values of &amp;lt;math&amp;gt;\kappa_1,\kappa_2&amp;lt;/math&amp;gt; were improved to&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_1 := (\delta_1 + \sum_{j=1}^{1/4\varpi} \delta_1^j \delta_{2,j}^2 + \delta_1 k_0 \log(1+\frac{1}{4\varpi})) \binom{k_0+2l_0}{k_0}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_2 := (\delta_1 (1+4\varpi) + \sum_{j=1}^{1/4\varpi} \delta_1^j (1+4\varpi)^j \delta_{2,j}^2 + \delta_1 (1+4\varpi) k_0 \log(1+\frac{1}{4\varpi}) \binom{k_0+2l_0+1}{k_0-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \delta_{2,j} := \prod_{i=1}^j (1 + k_0 \log(1+\frac{1}{i}) )&amp;lt;/math&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
again, see [http://terrytao.files.wordpress.com/2013/05/bounds.pdf these notes].   As before, &amp;lt;math&amp;gt;l_0&amp;lt;/math&amp;gt; can be taken to be non-integer.&lt;br /&gt;
&lt;br /&gt;
The constraint was then [http://terrytao.wordpress.com/2013/06/03/the-prime-tuples-conjecture-sieve-theory-and-the-work-of-goldston-pintz-yildirim-motohashi-pintz-and-zhang/ improved further in this post] to deduce &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; from &amp;lt;math&amp;gt;MPZ[\varpi,\delta]&amp;lt;/math&amp;gt; whenever&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) &amp;gt; (1 + \frac{1}{2l_0+1}) (1 + \frac{2l_0+1}{k_0}) (1 + \kappa)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa = \sum_{1 \leq n \leq \frac{1+4\varpi}{2\delta}} (1 - \frac{2n\delta}{1+4\varpi})^{k_0/2+l_0} \prod_{j=1}^n (1+3k_0 \log(1+\frac{1}{j}))&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Using the optimal Bessel weight, this condition was improved to&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) &amp;gt; \frac{j^{2}_{k_0-2}}{k_0(k_0-1)} (1 + \kappa)&amp;lt;/math&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
again, see [http://terrytao.wordpress.com/2013/06/03/the-prime-tuples-conjecture-sieve-theory-and-the-work-of-goldston-pintz-yildirim-motohashi-pintz-and-zhang/ this post].&lt;br /&gt;
&lt;br /&gt;
A variant of this criterion was developed using the elementary Selberg sieve in [http://terrytao.wordpress.com/2013/06/08/the-elementary-selberg-sieve-and-bounded-prime-gaps/ this post], but never used.  A subsequent refined criterion was established in [http://terrytao.wordpress.com/2013/06/11/further-analysis-of-the-truncated-gpy-sieve/ this post], namely that&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) (1-\kappa&#039;) &amp;gt; \frac{j^{2}_{k_0-2}}{k_0(k_0-1)} (1 + \kappa)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa := \sum_{1 \leq n &amp;lt; \frac{1+4\varpi}{2\delta}} \frac{3^n+1}{2} \frac{k_0^n}{n!} (\int_{4\delta/(1+\varpi)}^1 (1-t)^{k_0/2} \frac{dt}{t})^n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa&#039; := \sum_{2 \leq n &amp;lt; \frac{1+4\varpi}{2\delta}} \frac{3^n-1}{2} \frac{(k_0-1)^n}{n!} (\int_{4\delta/(1+\varpi)}^1 (1-t)^{(k_0-1)/2} \frac{dt}{t})^n.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slight refinement in [http://terrytao.wordpress.com/2013/06/11/further-analysis-of-the-truncated-gpy-sieve/#comment-234845 this comment] allows the condition &amp;lt;math&amp;gt;n \geq 2&amp;lt;/math&amp;gt; in the definition of &amp;lt;math&amp;gt;\kappa&#039;&amp;lt;/math&amp;gt; to be raised to &amp;lt;math&amp;gt;n \geq 3&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
An [http://terrytao.wordpress.com/2013/06/18/a-truncated-elementary-selberg-sieve-of-pintz argument of Pintz] yields the following improved values of &amp;lt;math&amp;gt;\kappa,\kappa&#039;&amp;lt;/math&amp;gt; in the above criterion:&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa := 0 &amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa&#039; := 2 \kappa_1 + 2 \kappa_2&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_1 := \int_{4\delta/(1+4\varpi)}^1 (1-t)^{(k_0-1)/2} \frac{dt}{t}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_2 := (k_0-1) \int_{4\delta/(1+4\varpi)}^1 (1-t)^{k_0-1} \frac{dt}{t}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
== Converting MPZ&#039; to DHL ==&lt;br /&gt;
&lt;br /&gt;
An efficient [http://terrytao.wordpress.com/2013/06/18/a-truncated-elementary-selberg-sieve-of-pintz argument of Pintz], based on the elementary Selberg sieve, allows one to deduce &amp;lt;math&amp;gt;DHL[k_0,2]&amp;lt;/math&amp;gt; from &amp;lt;math&amp;gt;MPZ&#039;[\varpi,\delta]&amp;lt;/math&amp;gt; with almost no loss with respect to the &amp;lt;math&amp;gt;\delta&amp;lt;/math&amp;gt; parameter.  As currently optimised, the criterion takes the form&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; (1+4\varpi) (1-2\kappa_1 - 2\kappa_2 - 2\kappa_3) &amp;gt; \frac{j_{k_0-2}}{k_0(k_0-1)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_1 := \int_{\theta}^1 (1-t)^{(k_0-1)/2} \frac{dt}{t}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_2 := (k_0-1) \int_{\theta}^1 (1-t)^{k_0-1} \frac{dt}{t}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \kappa_3 := \tilde \theta \frac{J_{k_0-2}(\sqrt{\tilde \theta} j_{k_0-2})^2 - J_{k_0-3}(\sqrt{\tilde \theta} j_{k_0-2}) J_{k_0-1}(\sqrt{\tilde \theta} j_{k_0-2})}{ J_{k_0-3}(j_{k_0-2})^2 } &lt;br /&gt;
\exp( A + (k_0-1) \int_{\tilde \delta}^\theta e^{-(A+2\alpha)t} \frac{dt}{t} )&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt; \alpha := \frac{j_{k_0-2}^2}{4(k_0-1)}&amp;lt;/math&amp;gt;&lt;br /&gt;
:&amp;lt;math&amp;gt; \theta := \frac{\delta&#039;}{1/4 + \varpi}&amp;lt;/math&amp;gt;&lt;br /&gt;
:&amp;lt;math&amp;gt; \tilde \theta := \frac{(\delta&#039; - \delta)/2 + \varpi}{1/4 + \varpi}&amp;lt;/math&amp;gt;&lt;br /&gt;
:&amp;lt;math&amp;gt; \tilde \delta := \frac{\delta}{1/4 + \varpi}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
and &amp;lt;math&amp;gt;A&amp;gt;0&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\delta \leq \delta&#039; \leq \frac{1}{4} + \varpi&amp;lt;/math&amp;gt; are parameters one is free to optimise over.&lt;br /&gt;
&lt;br /&gt;
Here is some simple Maple code to verify the above criterion for given choices of &amp;lt;math&amp;gt;k_0,\varpi,\delta,\delta&#039;,A&amp;lt;/math&amp;gt;:&lt;br /&gt;
&lt;br /&gt;
 k0 := [INSERT VALUE HERE];&lt;br /&gt;
 varpi := [INSERT VALUE HERE];&lt;br /&gt;
 delta := [INSERT VALUE HERE];&lt;br /&gt;
 deltap := [INSERT VALUE HERE]; &lt;br /&gt;
 A := [INSERT VALUE HERE];&lt;br /&gt;
 theta := deltap / (1/4 + varpi);&lt;br /&gt;
 thetat := ((deltap - delta)/2 + varpi) / (1/4 + varpi);&lt;br /&gt;
 deltat := delta / (1/4 + varpi);&lt;br /&gt;
 j := BesselJZeros(k0-2,1);&lt;br /&gt;
 eps := 1 - j^2 / (k0 * (k0-1) * (1+4*varpi));&lt;br /&gt;
 kappa1 := int( (1-t)^((k0-1)/2)/t, t = theta..1, numeric);&lt;br /&gt;
 kappa2 := (k0-1) * int( (1-t)^(k0-1)/t, t=theta..1, numeric);&lt;br /&gt;
 alpha := j^2 / (4 * (k0-1));&lt;br /&gt;
 e := exp( A + (k0-1) * int( exp(-(A+2*alpha)*t)/t, t=deltat..theta, numeric ) );&lt;br /&gt;
 gd := (j^2/2) * BesselJ(k0-3,j)^2;&lt;br /&gt;
 tn := sqrt(thetat)*j;&lt;br /&gt;
 gn := (tn^2/2) * (BesselJ(k0-2,tn)^2 - BesselJ(k0-3,tn)*BesselJ(k0-1,tn));&lt;br /&gt;
 kappa3 := (gn/gd) * e;&lt;br /&gt;
 eps2 := 2*(kappa1+kappa2+kappa3);&lt;br /&gt;
 # we win if eps2 &amp;lt; eps&lt;/div&gt;</summary>
		<author><name>Pace</name></author>
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