{ "id": "0711.1800", "version": "v2", "published": "2007-11-12T15:29:00.000Z", "updated": "2007-11-13T14:57:39.000Z", "title": "Arithmetic and Geometric Progressions in Productsets over Finite Fields", "authors": [ "Igor E. Shparlinski" ], "categories": [ "math.NT", "math.CO" ], "abstract": "Given two sets $\\cA, \\cB \\subseteq \\F_q$ of elements of the finite field $\\F_q$ of $q$ elements, we show that the productset $$ \\cA\\cB = \\{ab | a \\in \\cA, b \\in\\cB\\} $$ contains an arithmetic progression of length $k \\ge 3$ provided that $k