BEGIN:VCALENDAR
VERSION:2.0
PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Cosmin Pohoata (Emory University)
DTSTART:20260716T183000Z
DTEND:20260716T185500Z
DTSTAMP:20260710T111523Z
UID:CANT2026/52
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/CANT2026/52/
 ">Sidon sets in the squares\, repeated distances\, and the Elekes-Ronyai p
 roblem</a>\nby Cosmin Pohoata (Emory University) as part of Combinatorial 
 and additive number theory seminar (CANT 2026)\n\nLecture held in Science 
 Center in the CUNY Graduate Center (4th floor).\n\nAbstract\nWe discuss a 
 new combinatorial large-sieve method that uses algebraic splitting modulo 
 many small primes to turn local congruence restrictions into global constr
 aints on repeated values. This has various applications\, for example: (i)
  every Sidon subset of $\\{1^2\, 2^2\, \\ldots\, N^2\\}$ has size at most 
 $N \\cdot \\exp(-c \\log N / \\log \\log N)$\, the first super-polylogarit
 hmic saving for a classical problem of Alon and Erdös\; (ii) a new upper 
 bound on the largest subset of $[N]^2$ with no repeated distances\, a prob
 lem of Erdös and Guy\; and (iii) a new upper bound on the largest subset 
 of $[N]^2$ with no isosceles triangle\, a problem recently popularized by 
 Charton\, Ellenberg\, Wagner\, and Williamson. Based on recent joint work 
 with Ernie Croot\, Junzhe Mao\, Adam Sheffer\, and Kyle Yip. We will also 
 discuss how these ideas recently led to a counterexample for the Elekes--R
 \\'onyai problem (and to a few other constructions).\n
LOCATION:https://researchseminars.org/talk/CANT2026/52/
END:VEVENT
END:VCALENDAR