Theorem 19.21 1905

Description: Theorem 19.21 of [Margaris] p. 90. The hypothesis can be thought of as " is not free in ." See 19.21v 1729 for a version requiring fewer axioms. See also 19.21h 1907. (Contributed by NM, 14-May-1993.) (Revised by Mario Carneiro, 24-Sep-2016.)

Hypothesis

Ref	Expression
19.21.1

Assertion

Ref	Expression
19.21

Proof of Theorem 19.21

Step	Hyp	Ref	Expression
1		19.21.1	. 2
2		19.21t 1904	. 2
3	1, 2	ax-mp 5	1

Syntax hints:  ->wi 4  <->wb 184  A.wal 1393  F/wnf 1616

This theorem is referenced by:  19.21-2  1906  19.21h  1907  stdpc5  1908  nf3  1961  19.32  1967  19.21vOLD  1981  19.12vv  1986  cbv1  2017  axc14  2113  r2alf  2833  r2alfOLD  2834  19.12b  29234  wl-dral1d  29984  mpt2bi123f  30571  bj-biexal2  34260  bj-bialal  34262  bj-cbv1v  34292

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1618  ax-4 1631  ax-5 1704  ax-6 1747  ax-7 1790  ax-10 1837  ax-12 1854

This theorem depends on definitions:  df-bi 185  df-ex 1613  df-nf 1617