Theorem ax11dgen

Description: Degenerate instance of ax-11 where bundled variables x and y have a common substitution. Uses only Tarski's FOL axiom schemes. (Contributed by NM, 13-Apr-2017)

	Ref	Expression
Assertion	ax11dgen	$$⊢\forall x\forall x\phi \to \forall x\forall x\phi$$

Proof

Step	Hyp	Ref	Expression
1		id	$$⊢\forall x\forall x\phi \to \forall x\forall x\phi$$