The largest sum-free subsequence from a sequence of $n$ numbers
S. L. G. Choi · Proceedings of the American Mathematical Society · 1973
Let $g(n)$ denote the largest integer so that from any sequence of $n$ real numbers one can always select a sum-free subsequence of $g(n)$ numbers. Erdös has shown that $g(n) > {2^{ - 1/2}}{n^{1/2}}$. In this paper we obtain an improved estimate by a different method.