Zero-free regions

The table below lists various regions of the [math]\displaystyle{ (t,y,x) }[/math] parameter space where [math]\displaystyle{ H_t(x+iy) }[/math] is known to be non-zero. In some cases the parameter

[math]\displaystyle{ N := \lfloor \sqrt{\frac{x}{4\pi} + \frac{t}{16}} \rfloor }[/math]

is used.

Date	[math]\displaystyle{ t }[/math]	[math]\displaystyle{ y }[/math]	[math]\displaystyle{ x }[/math]	From	Method	Comments
1950	[math]\displaystyle{ t \geq 0 }[/math]	[math]\displaystyle{ y \gt \sqrt{\max(1-2t,0)} }[/math]	Any	De Bruijn	Theorem 13 of de Bruijn
2009	[math]\displaystyle{ t \gt 0 }[/math]	[math]\displaystyle{ y \gt 0 }[/math]	[math]\displaystyle{ x \geq C(t) }[/math]	Ki-Kim-Lee	Theorem 1.3 of Ki-Kim-Lee	[math]\displaystyle{ C(t) }[/math] is not given explicitly.
Mar 7 2018	0.4	0.4	[math]\displaystyle{ N \geq 2000 }[/math] ([math]\displaystyle{ x \geq 5.03 \times 10^7 }[/math])	Tao	Analytic lower bounds on [math]\displaystyle{ A^{eff}+B^{eff} / B^{eff}_0 }[/math] and analytic upper bounds on error terms	Can be extended to the range [math]\displaystyle{ 0.4 \leq y \leq 0.45 }[/math]
Mar 10 2018	0.4	0.4	[math]\displaystyle{ 151 \leq N \leq 300 }[/math] ([math]\displaystyle{ 2.87 \times 10^5 \leq x \leq 1.13 \times 10^6 }[/math])	KM	Mesh evaluation of [math]\displaystyle{ A^{eff}+B^{eff} / B^{eff}_0 }[/math] and upper bounds on error terms
Mar 11 2018	0.4	0.4	[math]\displaystyle{ 300 \leq N \leq 2000 }[/math] ([math]\displaystyle{ 1.13 \times 10^6 \leq x \leq 5.03 \times 10^7 }[/math])	KM	Analytic lower bounds on [math]\displaystyle{ A^{eff}+B^{eff} / B^{eff}_0 }[/math] and upper bounds on error terms
Mar 11 2018	0.4	0.4	[math]\displaystyle{ 20 \leq N \leq 150 }[/math] ([math]\displaystyle{ 5026 \leq x \leq 2.87 \times 10^5 }[/math])	Rudolph & [1]	Mesh evaluation of [math]\displaystyle{ A^{eff}+B^{eff} / B^{eff}_0 }[/math] and upper bounds on error terms