Cameron-Erdos Theorem

The Cameron-Erdos theorem, in combinatorics, concerns the number of sum-free sets contained in the integers from 1 to N, establishing that this count is O(2 to the power N/2). Peter Cameron and Paul Erdos formulated the statement as a conjecture in 1988, and it was proved independently by Ben Green and by Alexander Sapozhenko in 2003; the result reflects that every subset of the roughly N/2 odd numbers in that range is automatically sum-free, since two odd numbers never sum to an odd number, and shows that such odd-only subsets make up a constant fraction of all sum-free sets. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/