Freiman's theorem

The result is due to Gregory Freiman (1964, 1966).

Freiman's theorem

1. (mathematics) In additive combinatorics, a central result that indicates the approximate structure of sets whose sumset is small. It roughly states that if ${\displaystyle |A+A|/|A|}$ is small, then ${\displaystyle A}$ can be contained in a small generalized arithmetic progression.