Abstract:
A set $A$ of integers is called sum-free if $a+b\notin A$ for any $a,b\in A$.
For an arbitrary $\varepsilon>0$, let $s_{\varepsilon}(n)$ denote the number of sum-free sets in the segment $[(1/4+\varepsilon)n,n]$. We prove that for any $\varepsilon>0$ there exists a constant
$c =c(\varepsilon)$ such that
$$
s_{\varepsilon}(n)\le c2^{n/2}.
$$
This research was supported by the Russian Foundation for Basic Research, grant 01–01–00266.