Theorem hbnae 1955

Description: All variables are effectively bound in a distinct variable specifier. Lemma L19 in [Megill] p. 446 (p. 14 of the preprint). (Contributed by NM, 5-Aug-1993.)

Assertion

Ref	Expression
hbnae	|- (-. A.x x = y -> A.z -. A.x x = y)

Proof of Theorem hbnae

Step	Hyp	Ref	Expression
1		hbae 1953	. 2 |- (A.x x = y -> A.zA.x x = y)
2	1	hbn 1776	1 |- (-. A.x x = y -> A.z -. A.x x = y)

Syntax hints:  -. wn 3   -> wi 4  A.wal 1540

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925

This theorem depends on definitions:  df-bi 177  df-an 360  df-tru 1319  df-ex 1542  df-nf 1545

This theorem is referenced by:  hbnaes  1957  dvelimh  1964  eujustALT  2207