Definition:Slowly Progressing Mapping

Definition
Let $C$ be a class.

Let $g: C \to C$ be a progressing mapping from $C$ to $C$.

Then $g$ is slowly progressing :


 * $\forall x \in \Dom g: \card {\map g x} - \card x \le 1$

That is, for all $x$ in the domain of $g$, the set $\map g x$ has at most $1$ more element than $x$ does.