Bounded gaps between primes
Contents
World records
 [math]H[/math] is a quantity such that there are infinitely many pairs of consecutive primes of distance at most [math]H[/math] apart. Would like to be as small as possible (this is a primary goal of the Polymath8 project).
 [math]k_0[/math] is a quantity such that every admissible [math]k_0[/math]tuple has infinitely many translates which each contain at least two primes. Would like to be as small as possible. Improvements in [math]k_0[/math] lead to improvements in [math]H[/math]. (The relationship is roughly of the form [math]H \sim k_0 \log k_0[/math]; see the page on finding narrow admissible tuples.)
 [math]\varpi[/math] is a technical parameter related to a specialized form of the ElliottHalberstam conjecture. Would like to be as large as possible. Improvements in [math]\varpi[/math] lead to improvements in [math]k_0[/math]. (The relationship is roughly of the form [math]k_0 \sim \varpi^{3/2}[/math]; there is an active discussion on optimising these improvements here.) In more recent work, the single parameter [math]\varpi[/math] is replaced by a pair [math](\varpi,\delta)[/math] (in previous work we had [math]\delta=\varpi[/math]). Discussion on improving the values of [math](\varpi,\delta)[/math] is currently being held here. In this table, infinitesimal losses in [math]\delta,\varpi[/math] are ignored.
Date  [math]\varpi[/math] or [math](\varpi,\delta)[/math]  [math]k_0[/math]  [math]H[/math]  Comments 

14 May  1/1,168 (Zhang)  3,500,000 (Zhang)  70,000,000 (Zhang)  All subsequent work is based on Zhang's breakthrough paper. 
21 May  63,374,611 (Lewko)  Optimises Zhang's condition [math]\pi(H)\pi(k_0) \gt k_0[/math]; can be reduced by 1 by parity considerations  
28 May  59,874,594 (Trudgian)  Uses [math](p_{m+1},\ldots,p_{m+k_0})[/math] with [math]p_{m+1} \gt k_0[/math]  
30 May  59,470,640 (Morrison)
58,885,998? (Tao) 59,093,364 (Morrison) 57,554,086 (Morrison) 
Uses [math](p_{m+1},\ldots,p_{m+k_0})[/math] and then [math](\pm 1, \pm p_{m+1}, \ldots, \pm p_{m+k_0/21})[/math] following [HR1973], [HR1973b], [R1974] and optimises in m  
31 May  2,947,442 (Morrison)
2,618,607 (Morrison) 
48,112,378 (Morrison)
42,543,038 (Morrison) 42,342,946 (Morrison) 
Optimizes Zhang's condition [math]\omega\gt0[/math], and then uses an improved bound on [math]\delta_2[/math]  
1 Jun  42,342,924 (Tao)  Tiny improvement using the parity of [math]k_0[/math]  
2 Jun  866,605 (Morrison)  13,008,612 (Morrison)  Uses a further improvement on the quantity [math]\Sigma_2[/math] in Zhang's analysis (replacing the previous bounds on [math]\delta_2[/math])  
3 Jun  1/1,040? (v08ltu)  341,640 (Morrison)  4,982,086 (Morrison)
4,802,222 (Morrison) 
Uses a different method to establish [math]DHL[k_0,2][/math] that removes most of the inefficiency from Zhang's method. 
4 Jun  1/224?? (v08ltu)
1/240?? (v08ltu) 
4,801,744 (Sutherland)
4,788,240 (Sutherland) 
Uses asymmetric version of the HensleyRichards tuples  
5 Jun  34,429? (Paldi/v08ltu)  4,725,021 (Elsholtz)
4,717,560 (Sutherland) 397,110? (Sutherland) 4,656,298 (Sutherland) 389,922 (Sutherland) 388,310 (Sutherland) 388,284 (Castryck) 388,248 (Sutherland) 387,982 (Castryck) 387,974 (Castryck) 
[math]k_0[/math] bound uses the optimal Bessel function cutoff. Originally only provisional due to neglect of the kappa error, but then it was confirmed that the kappa error was within the allowed tolerance.
[math]H[/math] bound obtained by a hybrid Schinzel/greedy (or "greedygreedy") sieve  
6 Jun  

387,960 (Angelveit)
387,904 (Angeltveit)

Improved [math]H[/math]bounds based on experimentation with different residue classes and different intervals, and randomized tiebreaking in the greedy sieve. 
7 Jun 
[math]207 \varpi + 43\delta \lt \frac{1}{4}[/math] (v08ltu/Green) 
26,024? (vo8ltu) 
387,534 (pedantSutherland) 
Many of the results ended up being retracted due to a number of issues found in the most recent preprint of Pintz. 
June 8  286,224 (Sutherland)
285,752 (pedantSutherland) 
values of [math]\varpi,\delta,k_0[/math] now confirmed; most tuples available on dropbox. New bounds on [math]H[/math] obtained via iterated merging using a randomized greedy sieve.  
Jun 9  181,000*? (Pintz)  2,530,338*? (Pintz)  New bounds on [math]H[/math] obtained by interleaving iterated merging with local optimizations.  
Jun 10  23,283? (Harcos/v08ltu)  285,210 (Sutherland)  More efficient control of the [math]\kappa[/math] error using the fact that numbers with no small prime factor are usually coprime  
Jun 11  252,804 (Sutherland)  More refined local "adjustment" optimizations, as detailed here.
An issue with the [math]k_0[/math] computation has been discovered, but is in the process of being repaired.  
Jun 12  22,951 (Tao/v08ltu)
22,949 (Harcos) 
249,180 (Castryck)  Improved bound on [math]k_0[/math] avoids the technical issue in previous computations.  
Jun 13 
Legend:
 ?  unconfirmed or conditional
 ??  theoretical limit of an analysis, rather than a claimed record
 *  is majorized by an earlier but independent result
 strikethrough  values relied on a computation that has now been retracted
See also the article on Finding narrow admissible tuples for benchmark values of [math]H[/math] for various key values of [math]k_0[/math].
Polymath threads
 I just can’t resist: there are infinitely many pairs of primes at most 59470640 apart, Scott Morrison, 30 May 2013. Inactive
 The prime tuples conjecture, sieve theory, and the work of GoldstonPintzYildirim, MotohashiPintz, and Zhang, Terence Tao, 3 June 2013. Inactive
 Polymath proposal: bounded gaps between primes, Terence Tao, 4 June 2013. Active
 Online reading seminar for Zhang’s “bounded gaps between primes, Terence Tao, 4 June 2013. Active
 More narrow admissible sets, Scott Morrison, 5 June 2013. Active
 The elementary Selberg sieve and bounded prime gaps, Terence Tao, 8 June 2013. Inactive
 A combinatorial subset sum problem associated with bounded prime gaps, Terence Tao, 10 June 2013. Active
 Further analysis of the truncated GPY sieve, Terence Tao, 11 June 2013. Active
Code and data
 HenselyRichards sequences, Scott Morrison
 A mathematica notebook for finding k_0, Scott Morrison
 python implementation, Avi Levy
 ktuple pattern data, Thomas J Engelsma
 Sifted sequences, Vit Tucek
 Other sifted sequences, Christian Elsholtz
 Size of largest admissible tuples in intervals of length up to 1050, Clark and Jarvis
 C implementation of the "greedygreedy" algorithm, Andrew Sutherland
 Dropbox for sequences, pedant
 Spreadsheet for admissible sequences, Vit Tucek
 Java code for optimising a given tuple V1.0, Java code for optimising a given tuple V1.1, xfxie
Errata
Page numbers refer to the file linked to for the relevant paper.
 Errata for Zhang's "Bounded gaps between primes"
 Page 5: In the first display, [math]\mathcal{E}[/math] should be multiplied by [math]\mathcal{L}^{2k_0+2l_0}[/math], because [math]\lambda(n)^2[/math] in (2.2) can be that large, cf. (2.4).
 Page 14: In the final display, the constraint [math](n,d_1=1[/math] should be [math](n,d_1)=1[/math].
 Page 35: In the display after (10.5), the subscript on [math]{\mathcal J}_i[/math] should be deleted.
 Page 36: In the third display, a factor of [math]\tau(q_0r)^{O(1)}[/math] may be needed on the righthand side (but is ultimately harmless).
 Page 38: In the display after (10.14), [math]\xi(r,a;q_1,b_1;q_2,b_2;n,k)[/math] should be [math]\xi(r,a;k;q_1,b_1;q_2,b_2;n)[/math].
 Page 42: In (12.3), [math]B[/math] should probably be 2.
 Page 47: In the third display after (13.13), the condition [math]l \in {\mathcal I}_i(h)[/math] should be [math]l \in {\mathcal I}_i(sh)[/math].
 Page 49: In the top line, a comma in [math](h_1,h_2;,n_1,n_2)[/math] should be deleted.
 Page 51: In the penultimate display, one of the two consecutive commas should be deleted.
 Page 54: Three displays before (14.17), [math]\bar{r_2}(m_1+m_2)q[/math] should be [math]\bar{r_2}(m_1+m_2)/q[/math].
 Errata for MotohashiPintz's "A smoothed GPY sieve"
 Page 31: The estimation of (5.14) by (5.15) does not appear to be justified. In the text, it is claimed that the second summation in (5.14) can be treated by a variant of (4.15); however, whereas (5.14) contains a factor of [math](\log \frac{R}{D})^{2\ell+1}[/math], (4.15) contains instead a factor of [math](\log \frac{R/w}{K})^{2\ell+1}[/math] which is significantly smaller (K in (4.15) plays a similar role to D in (5.14)). As such, the crucial gain of [math]\exp(k\omega/3)[/math] in (4.15) does not seem to be available for estimating the second sum in (5.14).
 Errata for Pintz's "A note on bounded gaps between primes"
 Page 7: In (2.39), the exponent of [math]3a/2[/math] should instead be [math]5a/2[/math] (it comes from dividing (2.38) by (2.37)). This impacts the numerics for the rest of the paper.
 Page 8: The "easy calculation" that the relative error caused by discarding all but the smooth moduli appears to be unjustified, as it relies on the treatment of (5.14) in MotohashiPintz which has the issue pointed out in 2.1 above.
Other relevant blog posts
 Marker lecture III: “Small gaps between primes”, Terence Tao, 19 Nov 2008.
 The GoldstonPintzYildirim result, and how far do we have to walk to twin primes ?, Emmanuel Kowalski, 22 Jan 2009.
 Number Theory News, Peter Woit, 12 May 2013.
 Bounded Gaps Between Primes, Emily Riehl, 14 May 2013.
 Bounded gaps between primes!, Emmanuel Kowalski, 21 May 2013.
 Bounded gaps between primes: some grittier details, Emmanuel Kowalski, 4 June 2013.
 Bound on prime gaps bound decreasing by leaps and bounds, Christian Perfect, 8 June 2013.
MathOverflow
 Philosophy behind Yitang Zhang’s work on the Twin Primes Conjecture, 20 May 2013.
 A technical question related to Zhang’s result of bounded prime gaps, 25 May 2013.
 How does Yitang Zhang use Cauchy’s inequality and Theorem 2 to obtain the error term coming from the [math]S_2[/math] sum, 31 May 2013.
 Tightening Zhang’s bound, 3 June 2013.
 Does Zhang’s theorem generalize to 3 or more primes in an interval of fixed length?, 3 June 2013.
Wikipedia and other references
 Bessel function
 BombieriVinogradov theorem
 BrunTitchmarsh theorem
 Dispersion method
 Prime gap
 Second HardyLittlewood conjecture
 Twin prime conjecture
Recent papers and notes
 On the exponent of distribution of the ternary divisor function, Étienne Fouvry, Emmanuel Kowalski, Philippe Michel, 11 Apr 2013.
 On the optimal weight function in the GoldstonPintzYildirim method for finding small gaps between consecutive primes, Bálint Farkas, János Pintz and Szilárd Gy. Révész, To appear in: Paul Turán Memorial Volume: Number Theory, Analysis and Combinatorics, de Gruyter, Berlin, 2013. 23 pages. arXiv
 Bounded gaps between primes, Yitang Zhang, to appear, Annals of Mathematics. Released 21 May, 2013.
 Polignac Numbers, Conjectures of Erdös on Gaps between Primes, Arithmetic Progressions in Primes, and the Bounded Gap Conjecture, Janos Pintz, 27 May 2013.
 A poor man's improvement on Zhang's result: there are infinitely many prime gaps less than 60 million, T. S. Trudgian, 28 May 2013.
 The FriedlanderIwaniec sum, É. Fouvry, E. Kowalski, Ph. Michel., May 2013.
 Notes on Zhang's prime gaps paper, Terence Tao, 1 June 2013.
 Bounded prime gaps in short intervals, Johan Andersson, 3 June 2013.
 Bounded length intervals containing two primes and an almostprime II, James Maynard, 5 June 2013.
 A note on bounded gaps between primes, Janos Pintz, 6 June 2013.
Media
 First proof that infinitely many prime numbers come in pairs, Maggie McKee, Nature, 14 May 2013.
 Proof that an infinite number of primes are paired, Lisa Grossman, New Scientist, 14 May 2013.
 Unheralded Mathematician Bridges the Prime Gap, Erica Klarreich, Simons science news, 20 May 2013.
 The article also appeared on Wired as "Unknown Mathematician Proves Elusive Property of Prime Numbers".
 The Beauty of Bounded Gaps, Jordan Ellenberg, Slate, 22 May 2013.
 Game of proofs boosts prime pair result by millions, Jacob Aron, New Scientist, 4 June 2013.
Bibliography
Additional links for some of these references (e.g. to arXiv versions) would be greatly appreciated.
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 [BFI1987] Bombieri, E.; Friedlander, J. B.; Iwaniec, H. Primes in arithmetic progressions to large moduli. II. Math. Ann. 277 (1987), no. 3, 361–393. MathSciNet Article
 [BFI1989] Bombieri, E.; Friedlander, J. B.; Iwaniec, H. Primes in arithmetic progressions to large moduli. III. J. Amer. Math. Soc. 2 (1989), no. 2, 215–224. MathSciNet Article
 [B1995] Jörg Brüdern, Einführung in die analytische Zahlentheorie, Springer Verlag 1995
 [CJ2001] Clark, David A.; Jarvis, Norman C.; Dense admissible sequences. Math. Comp. 70 (2001), no. 236, 1713–1718 MathSciNet Article
 [FI1981] Fouvry, E.; Iwaniec, H. On a theorem of BombieriVinogradov type., Mathematika 27 (1980), no. 2, 135–152 (1981). MathSciNet Article
 [FI1983] Fouvry, E.; Iwaniec, H. Primes in arithmetic progressions. Acta Arith. 42 (1983), no. 2, 197–218. MathSciNet Article
 [FI1985] Friedlander, John B.; Iwaniec, Henryk, Incomplete Kloosterman sums and a divisor problem. With an appendix by Bryan J. Birch and Enrico Bombieri. Ann. of Math. (2) 121 (1985), no. 2, 319–350. MathSciNet JSTOR
 [GPY2009] Goldston, Daniel A.; Pintz, János; Yıldırım, Cem Y. Primes in tuples. I. Ann. of Math. (2) 170 (2009), no. 2, 819–862. arXiv MathSciNet
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 [HR1973b] Hensley, Douglas; Richards, Ian, Primes in intervals. Acta Arith. 25 (1973/74), 375–391. MathSciNet Article
 [MP2008] Motohashi, Yoichi; Pintz, János A smoothed GPY sieve. Bull. Lond. Math. Soc. 40 (2008), no. 2, 298–310. arXiv MathSciNet Article
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