Axiom:Axiom of Pairing

From ProofWiki
Jump to navigation Jump to search

Axiom

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

$\forall A: \forall B: \exists x: \forall y: \left({y \in x \iff y = A \lor y = B}\right)$

Thus it is possible to create a set containing any two sets that you have already created.

Otherwise known as the Axiom of the Unordered Pair.



The Axiom of Pairing can alternatively be stated as:

$\forall A: \forall B: \exists x: \forall y: \left({y \in x \implies y = A \lor y = B}\right)$

which guarantees the existence of a set that contains at least two elements.


Also see


Relation to other axioms

The Axiom of Pairing can be deduced as a consequence of:

$(1): \quad$ The Axiom of Infinity and the Axiom of Replacement: see Axiom of Pairing from Infinity and Replacement
$(2): \quad$ The Axiom of Powers and the Axiom of Replacement: see Axiom of Pairing from Powers and Replacement.


Sources