Theorem vtocl2ga 2922

Description: Implicit substitution of 2 classes for 2 setvar variables. (Contributed by NM, 20-Aug-1995.)

Hypotheses

Ref	Expression
vtocl2ga.1	|- (x = A -> (ph <-> ps))
vtocl2ga.2	|- (y = B -> (ps <-> ch))
vtocl2ga.3	|- ((x e. C /\ y e. D) -> ph)

Assertion

Ref	Expression
vtocl2ga	|- ((A e. C /\ B e. D) -> ch)

Distinct variable groups:   x,y,A   y,B   x,C,y   x,D,y   ps,x   ch,y

Allowed substitution hints:   ph(x,y)   ps(y)   ch(x)   B(x)

Proof of Theorem vtocl2ga

Step	Hyp	Ref	Expression
1		nfcv 2489	. 2 |- F/_xA
2		nfcv 2489	. 2 |- F/_yA
3		nfcv 2489	. 2 |- F/_yB
4		nfv 1619	. 2 |- F/xps
5		nfv 1619	. 2 |- F/ych
6		vtocl2ga.1	. 2 |- (x = A -> (ph <-> ps))
7		vtocl2ga.2	. 2 |- (y = B -> (ps <-> ch))
8		vtocl2ga.3	. 2 |- ((x e. C /\ y e. D) -> ph)
9	1, 2, 3, 4, 5, 6, 7, 8	vtocl2gaf 2921	1 |- ((A e. C /\ B e. D) -> ch)

Syntax hints:   -> wi 4   <-> wb 176   /\ wa 358   = wceq 1642   e. wcel 1710

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  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-v 2861

This theorem is referenced by:  f1fveq  5473  caovcan  5628