These are the commutative property, the associative property, the identity property ( 2 is the exponentiative identity for commutative exponentiation, ) the special-value property ( for addition; this number is-\ infty; for multiplication it is 0; for commutative exponentiation it is 1 ); and the inverse property ( the exponentiative inverse of a is the number b for which commexp ( a, b ) = 2.