Theorem ax13dgen4 2017

Description: Degenerate instance of ax-13 2246 where bundled variables x, y, and z have a common substitution. Uses only Tarski's FOL axiom schemes. (Contributed by NM, 13-Apr-2017.) Reduce axiom usage. (Revised by Wolf Lammen, 10-Oct-2021.)

Assertion

Ref	Expression
ax13dgen4	|- ( -. x = x -> ( x = x -> A. x x = x ) )

Proof of Theorem ax13dgen4

Step	Hyp	Ref	Expression
1		pm2.21 120	1 |- ( -. x = x -> ( x = x -> A. x x = x ) )

Syntax hints:   -. wn 3   -> wi 4   A.wal 1481

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem is referenced by: (None)