Theorem ax8v 1993

Description: Weakened version of ax-8 1992, with a dv condition on x , y. This should be the only proof referencing ax-8 1992, and it should be referenced only by its two weakened versions ax8v1 1994 and ax8v2 1995, from which ax-8 1992 is then rederived as ax8 1996, which shows that either ax8v 1993 or the conjunction of ax8v1 1994 and ax8v2 1995 is sufficient. (Contributed by BJ, 7-Dec-2020.) Use ax8 1996 instead. (New usage is discouraged.)

Assertion

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

Distinct variable group:   x, y

Proof of Theorem ax8v

Step	Hyp	Ref	Expression
1		ax-8 1992	1 |- ( x = y -> ( x e. z -> y e. z ) )

Syntax hints:   -> wi 4

This theorem was proved from axioms:  ax-8 1992

This theorem is referenced by:  ax8v1  1994  ax8v2  1995