Cameron–Erdős conjecture

The statement that the number of sum-free sets contained in $\{1,\ldots,N\}$ is $O\left({2^{N/2}}\right)$. The conjecture was stated by Peter Cameron and Paul Erdős in 1988. It was proved by Ben Green in 2003.

References

• P.J. Cameron and P. Erdős, On the number of sets of integers with various properties, Number theory (Banff, 1988), de Gruyter, Berlin 1990, pp.61-79 Zbl 0695.10048
• B. Green, The Cameron-Erdős conjecture, Bulletin of the London Mathematical Society 36 (2004) pp.769-778 Zbl 1074.11013