In mathematics, an antihomomorphism is a type of function defined on sets with multiplication that reverses the order of multiplication. An antiautomorphism is a bijective antihomomorphism, i.e., an antiisomorphism, from a set to itself. From being bijective it follows that it has an inverse, and that the inverse is also an antiautomorphism.

In mathematics, an antihomomorphism is a type of function defined on sets with multiplication that reverses the order of multiplication. An antiautomorphism is a bijective antihomomorphism, i.e., an antiisomorphism, from a set to itself. From being bijective it follows that it has an inverse, and that the inverse is also an antiautomorphism.