Involution

An involution is a function whose inverse is itself.

Examples

• The function has the inverse , which is the same function, and thus is an involution.
• The logical NOT is an involution because $\neg \neg p} \equiv p$ (Error compiling LaTeX. Unknown error_msg).
• The additive negation is an involution because .
• The multiplicative inverse is an involution because . In fact, for any , f(x)=\frac{n}{x}$is an involution.

== Properties ==

• An function is an involution [[iff]] it is symmetric about the line$ (Error compiling LaTeX. Unknown error_msg)f(x)=x$ in the coordinate plane.

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