In mathematics, an **involution** is a function that is it’s own inverse. Involutions are sometimes also called **involutory functions**. So, for an involutory function *f:*

for all *x* in the domain of *f*.

In mathematics, an **involution** is a function that is it’s own inverse. Involutions are sometimes also called **involutory functions**. So, for an involutory function *f:*

for all *x* in the domain of *f*.