Theorem aecoms-o

Description: A commutation rule for identical variable specifiers. Version of aecoms using ax-c11 . (Contributed by NM, 10-May-1993) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypothesis	alequcoms-o.1	$$⊢\forall xx=y\to \phi$$
Assertion	aecoms-o	$$⊢\forall yy=x\to \phi$$

Proof

Step	Hyp	Ref	Expression
1		alequcoms-o.1	$$⊢\forall xx=y\to \phi$$
2		aecom-o	$$⊢\forall yy=x\to \forall xx=y$$
3	2 1	syl	$$⊢\forall yy=x\to \phi$$