Given M1 = {m | M = x square - y square, X is an integer, y is an integer}, M2 = {m | M = 2K + 1 or M = 4K, K is an integer} to prove M 1 = m 2

Given M1 = {m | M = x square - y square, X is an integer, y is an integer}, M2 = {m | M = 2K + 1 or M = 4K, K is an integer} to prove M 1 = m 2

Discuss the three cases of X and Y being odd and even respectively