Definition:Progressing Mapping

Definition
Let $C$ be a set of sets or a class of sets.

Let $f: C \to C$ be a mapping from $C$ to $C$.

Then $f$ is inflationary :


 * $\forall x: x \in C \implies x \subseteq f \left({x}\right)$

That is, for each $x \in C$, $x$ is a subset of $f \left({x}\right)$.