Theorem vtocl2ga 2891

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 2392	. 2 |- F/_ x A
2		nfcv 2392	. 2 |- F/_ y A
3		nfcv 2392	. 2 |- F/_ y B
4		nfv 1581	. 2 |- F/ x ps
5		nfv 1581	. 2 |- F/ y ch
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 2890	1 |- ( ( A e. C /\ B e. D ) -> ch )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   = wceq 1402   e. wcel 2209

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 721  ax-5 1500  ax-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-8 1557  ax-10 1558  ax-11 1559  ax-i12 1560  ax-bndl 1562  ax-4 1563  ax-17 1579  ax-i9 1583  ax-ial 1587  ax-i5r 1588  ax-ext 2220

This theorem depends on definitions:  df-bi 117  df-tru 1405  df-nf 1514  df-sb 1816  df-clab 2225  df-cleq 2231  df-clel 2234  df-nfc 2381  df-v 2823

This theorem is referenced by:  vtocl4ga  2895  caovcan  6244  genipv  7866  wrdind  11472  fsumrelem  12216