Theorem ax8v1

Description: First of two weakened versions of ax8v , with an extra disjoint variable condition on x , z , see comments there. (Contributed by BJ, 7-Dec-2020)

	Ref	Expression
Assertion	ax8v1	|- ( x = y -> ( x e. z -> y e. z ) )

Proof

Step	Hyp	Ref	Expression
1		ax8v	|- ( x = y -> ( x e. z -> y e. z ) )