Theorem bj-dvv

Description: A special instance of bj-hbaeb2 . A lemma for distinct var metavariables. Note that the right-hand side is a closed formula (a sentence). (Contributed by BJ, 6-Oct-2018)

	Ref	Expression
Assertion	bj-dvv	$$⊢\forall xx=y\leftrightarrow \forall x\forall yx=y$$

Proof

Step	Hyp	Ref	Expression
1		bj-hbaeb2	$$⊢\forall xx=y\leftrightarrow \forall x\forall yx=y$$