The '''Axiom of Foundation''' is the most recent of the [[axiom]]s of [[Zermelo-Fraenkel]] set theory to be added to the list. It states that for every set ''A'' the sequence: | The '''Axiom of Foundation''' is the most recent of the [[axiom]]s of [[Zermelo-Fraenkel]] set theory to be added to the list. It states that for every set ''A'' the sequence: |