Theorem rextpg 3424

Description: Convert a quantification over a triple to a disjunction. (Contributed by Mario Carneiro, 23-Apr-2015.)

Hypotheses

Ref	Expression
ralprg.1	|- ( x = A -> ( ph <-> ps ) )
ralprg.2	|- ( x = B -> ( ph <-> ch ) )
raltpg.3	|- ( x = C -> ( ph <-> th ) )

Assertion

Ref	Expression
rextpg	|- ( ( A e. V /\ B e. W /\ C e. X ) -> ( E. x e. { A , B , C } ph <-> ( ps \/ ch \/ th ) ) )

Distinct variable groups:   x, A   x, B   x, C   ps, x   ch, x   th, x

Allowed substitution hints:   ph( x)   V( x)   W( x)   X( x)

Proof of Theorem rextpg

Step	Hyp	Ref	Expression
1		ralprg.1	. . . . . 6 |- ( x = A -> ( ph <-> ps ) )
2		ralprg.2	. . . . . 6 |- ( x = B -> ( ph <-> ch ) )
3	1, 2	rexprg 3422	. . . . 5 |- ( ( A e. V /\ B e. W ) -> ( E. x e. { A , B } ph <-> ( ps \/ ch ) ) )
4	3	orbi1d 705	. . . 4 |- ( ( A e. V /\ B e. W ) -> ( ( E. x e. { A , B } ph \/ E. x e. { C } ph ) <-> ( ( ps \/ ch ) \/ E. x e. { C } ph ) ) )
5		raltpg.3	. . . . . 6 |- ( x = C -> ( ph <-> th ) )
6	5	rexsng 3412	. . . . 5 |- ( C e. X -> ( E. x e. { C } ph <-> th ) )
7	6	orbi2d 704	. . . 4 |- ( C e. X -> ( ( ( ps \/ ch ) \/ E. x e. { C } ph ) <-> ( ( ps \/ ch ) \/ th ) ) )
8	4, 7	sylan9bb 435	. . 3 |- ( ( ( A e. V /\ B e. W ) /\ C e. X ) -> ( ( E. x e. { A , B } ph \/ E. x e. { C } ph ) <-> ( ( ps \/ ch ) \/ th ) ) )
9	8	3impa 1099	. 2 |- ( ( A e. V /\ B e. W /\ C e. X ) -> ( ( E. x e. { A , B } ph \/ E. x e. { C } ph ) <-> ( ( ps \/ ch ) \/ th ) ) )
10		df-tp 3383	. . . 4 |- { A , B , C } = ( { A , B } u. { C } )
11	10	rexeqi 2510	. . 3 |- ( E. x e. { A , B , C } ph <-> E. x e. ( { A , B } u. { C } ) ph )
12		rexun 3123	. . 3 |- ( E. x e. ( { A , B } u. { C } ) ph <-> ( E. x e. { A , B } ph \/ E. x e. { C } ph ) )
13	11, 12	bitri 173	. 2 |- ( E. x e. { A , B , C } ph <-> ( E. x e. { A , B } ph \/ E. x e. { C } ph ) )
14		df-3or 886	. 2 |- ( ( ps \/ ch \/ th ) <-> ( ( ps \/ ch ) \/ th ) )
15	9, 13, 14	3bitr4g 212	1 |- ( ( A e. V /\ B e. W /\ C e. X ) -> ( E. x e. { A , B , C } ph <-> ( ps \/ ch \/ th ) ) )

Syntax hints:   -> wi 4   /\ wa 97   <-> wb 98   \/ wo 629   \/ w3o 884   /\ w3a 885   = wceq 1243   e. wcel 1393   E.wrex 2307   u. cun 2915   {csn 3375   {cpr 3376   {ctp 3377

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022

This theorem depends on definitions:  df-bi 110  df-3or 886  df-3an 887  df-tru 1246  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-rex 2312  df-v 2559  df-sbc 2765  df-un 2922  df-sn 3381  df-pr 3382  df-tp 3383

This theorem is referenced by:  rextp  3428