Axiom:Axiom of Pairing/Set Theory/Formulation 1

Axiom
For any two sets, there exists a set to which only those two sets are elements:


 * $\forall A: \forall B: \exists x: \forall y: \paren {y \in x \iff y = A \lor y = B}$

Thus it is possible to create a set that contains as elements any two sets that have already been created.

Also see

 * Equivalence of Definitions of Axiom of Pairing