What is this boolean operation?

Question

a and b - are my bool-variables. ? - is some unknown operation Help my to find operation in expression a ? b to get following results:

0 ? 0 = 1
0 ? 1 = 0
1 ? 0 = 0
1 ? 1 = 1

Answer 1

That looks like the truth table for XNOR, aka logical equality. See https://en.wikipedia.org/wiki/Truth_table#Logical_equality.

Answer 2

This is XNOR boolean operation.