Consider a binary operation # that is closed under the set of integers (if a and b are integers, then a#b is an integer).

Assume that, for all integers a and b, it is true that (a#b)#a=b.

Prove that a#(b#a)=b.

If memory serves... XOR would be one such operator (matching the description of this problem).

--- SK

Edited on April 16, 2004, 4:08 am

Posted by SilverKnight on 2003-10-17 14:58:38