Theorem equcomiv

Description: Weaker form of equcomi with a disjoint variable condition on x , y . This is an intermediate step and equcomi is fully recovered later. (Contributed by BJ, 7-Dec-2020)

	Ref	Expression
Assertion	equcomiv	$$⊢x=y\to y=x$$

Proof

Step	Hyp	Ref	Expression
1		equid	$$⊢x=x$$
2		ax7v2	$$⊢x=y\to \left(x=x\to y=x\right)$$
3	1 2	mpi	$$⊢x=y\to y=x$$