Georgia Institute of Technology, School of Mathematics, 125 Skiles, Atlanta, GA 30332, USA
Abstract:
Given a density 0<σ?1, we show for all sufficiently large primes p that if S⊆Z/pZ has the least number of three-term arithmetic progressions among all sets with at least σp elements, then S contains an arithmetic progression of length at least log1/4+o(1)p.