ThmDex – An index of mathematical definitions, results, and conjectures.
Formulation F9761 on D702: Involution
F9761
Formulation 2
Let $f : X \to X$ be a D18: Map such that
(i) $f$ is an D976: Invertible map
(ii) $f^{-1}$ is an D216: Inverse map of $f$
Then $f$ is an involution if and only if \begin{equation} f = f^{-1} \end{equation}