Theorem bj-axext4 32770

Description: Remove dependency on ax-13 2246 from axext4 2606. (Contributed by BJ, 6-Oct-2019.) (Proof modification is discouraged.)

Assertion

Ref	Expression
bj-axext4	|- ( x = y <-> A. z ( z e. x <-> z e. y ) )

Distinct variable groups:   x, z   y, z

Proof of Theorem bj-axext4

Step	Hyp	Ref	Expression
1		bj-elequ2g 32666	. 2 |- ( x = y -> A. z ( z e. x <-> z e. y ) )
2		bj-axext3 32769	. 2 |- ( A. z ( z e. x <-> z e. y ) -> x = y )
3	1, 2	impbii 199	1 |- ( x = y <-> A. z ( z e. x <-> z e. y ) )

Syntax hints:   <-> wb 196   A.wal 1481

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-ext 2602

This theorem depends on definitions:  df-bi 197  df-an 386  df-ex 1705

This theorem is referenced by: (None)