Theorem sbc19.21g 3074

Description: Substitution for a variable not free in antecedent affects only the consequent. (Contributed by NM, 11-Oct-2004.)

Hypothesis

Ref	Expression
sbcgf.1	|- F/ x ph

Assertion

Ref	Expression
sbc19.21g	|- ( A e. V -> ( [. A / x ]. ( ph -> ps ) <-> ( ph -> [. A / x ]. ps ) ) )

Proof of Theorem sbc19.21g

Step	Hyp	Ref	Expression
1		sbcimg 3047	. 2 |- ( A e. V -> ( [. A / x ]. ( ph -> ps ) <-> ( [. A / x ]. ph -> [. A / x ]. ps ) ) )
2		sbcgf.1	. . . 4 |- F/ x ph
3	2	sbcgf 3073	. . 3 |- ( A e. V -> ( [. A / x ]. ph <-> ph ) )
4	3	imbi1d 231	. 2 |- ( A e. V -> ( ( [. A / x ]. ph -> [. A / x ]. ps ) <-> ( ph -> [. A / x ]. ps ) ) )
5	1, 4	bitrd 188	1 |- ( A e. V -> ( [. A / x ]. ( ph -> ps ) <-> ( ph -> [. A / x ]. ps ) ) )

Syntax hints:   -> wi 4   <-> wb 105   F/wnf 1484   e. wcel 2178   [.wsbc 3005

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 711  ax-5 1471  ax-7 1472  ax-gen 1473  ax-ie1 1517  ax-ie2 1518  ax-8 1528  ax-10 1529  ax-11 1530  ax-i12 1531  ax-bndl 1533  ax-4 1534  ax-17 1550  ax-i9 1554  ax-ial 1558  ax-i5r 1559  ax-ext 2189

This theorem depends on definitions:  df-bi 117  df-tru 1376  df-nf 1485  df-sb 1787  df-clab 2194  df-cleq 2200  df-clel 2203  df-nfc 2339  df-v 2778  df-sbc 3006

This theorem is referenced by: (None)