A subset
A of integers is said to be
sum-free if
a+b
A for any
a,b
A. Let
s(n) be the number of sum-free sets in interval
[1,n] of integers. P.
Cameron and P. Erdős conjectured that
s(n)=O(2n/2). We show that
![View the MathML source View the MathML source](http://www.sciencedirect.com/cache/MiamiImageURL/B6V00-4R172Y1-1-N1/0?wchp=dGLbVlW-zSkWW)
for even
n and
![View the MathML source View the MathML source](http://www.sciencedirect.com/cache/MiamiImageURL/B6V00-4R172Y1-1-ND/0?wchp=dGLbVlW-zSkWW)
for odd
n, where
![View the MathML source View the MathML source](http://www.sciencedirect.com/cache/MiamiImageURL/B6V00-4R172Y1-1-NT/0?wchp=dGLbVlW-zSkWW)
are absolute constants, thereby proving the conjecture.