Аннотация:
We prove that there exists an absolute constant $c>0$ such that if an arithmetic progression
$\mathcal{P}$
modulo a prime number $p$ does not contain zero and has the cardinality less than $cp$, then it cannot be represented as a product of two subsets of cardinality greater than $1$, unless $\mathcal{P}=-\mathcal{P}$ or
$\mathcal{P}=\{-2r,r,4r\}$ for some residue $r$ modulo $p$.
Поступила в редакцию: 26.09.2013 Исправленный вариант: 23.05.2014 Принята в печать: 09.06.2014