\begin{definition}[Definition:Inverse Integral Operator]
Let $T: f \to F$ be an integral operator on a function $f$.
Let there be a (unitary) operator $T^{-1}: F \to f$ such that for a given $F \left({p}\right)$ there exists a unique $f \left({x}\right)$ such that $f = T \left({f}\right)$.
Then $T^{-1}$ is the '''inverse integral operator''' of $T$.
\end{definition}