Codex > Functions (Set Theory)
🅟 Apr 18, 2026
🅤 Jun 10, 2026
Definition 1. An involutory function or involution is a function $f : X \to Y$ such that \[f(f(x)) = x\] for all $x \in X$.
Definition 1.
An involutory function or involution is a function $f : X \to Y$ such that
for all $x \in X$.