===

a b | a=b

0 0 |  1 
0 1 |  0 
1 0 |  0
1 1 |  1

=/=

a b | a=/=b | neg(a=b)

0 0 |   0   |   0
0 1 |   1   |   1
1 0 |   1   |   1
1 1 |   0   |   0