Let A be a set of natural numbers in which if a , b belong to A (a>b) then either a\plus{}b or a\minus{}b belong to A ( both cases may be posible at the same time). Decide wheter there is or not a set A consisting on exactly 100 elements which has four elements x, y , z , w ( not necesarilly distinct) that satisfy x\minus{}y\equal{}512 and z\minus{}w\equal{}460
Daniel combinatorics proposedcombinatorics