MathDB
Sum and Sets of Integers

Source: SMO(O) 2014 #4

January 22, 2015
graph theorycombinatorics

Problem Statement

Let FF be a finite non-empty set of integers and let nn be a positive integer. Suppose that
\bullet Any xFx \in F may be written as x=y+zx=y+z for some yy, zFz \in F; \bullet If 1kn1 \leq k \leq n and x1x_1, ..., xkFx_k \in F, then x1++xk0x_1+\cdots+x_k \neq 0.
Show that FF has at least 2n+22n+2 elements.