involution

An **involution** is an endomorphism whose square is the identity morphism. Such an endomorphism must be an automorphism; indeed, it is its own inverse.

Where this makes sense, an **anti-involution** is an antihomomorphism instead of a homomorphism (so an antiendomorphism and necessarily an antiautomorphism).

Revised on February 27, 2014 08:35:57
by Urs Schreiber
(82.113.98.143)