Theorem ifpr 2423

Description: Membership of a conditional operator in an unordered pair.

Assertion

Ref	Expression
ifpr	|- ((A e. C /\ B e. D) -> if(ph, A, B) e. {A, B})

Proof of Theorem ifpr

Step	Hyp	Ref	Expression
1		ifcl 2376	. . 3 |- ((A e. V /\ B e. V) -> if(ph, A, B) e. V)
2		ifor 2377	. . . 4 |- (if(ph, A, B) = A \/ if(ph, A, B) = B)
3		elprg 2419	. . . 4 |- (if(ph, A, B) e. V -> (if(ph, A, B) e. {A, B} <-> (if(ph, A, B) = A \/ if(ph, A, B) = B)))
4	2, 3	mpbiri 194	. . 3 |- (if(ph, A, B) e. V -> if(ph, A, B) e. {A, B})
5	1, 4	syl 10	. 2 |- ((A e. V /\ B e. V) -> if(ph, A, B) e. {A, B})
6		elisset 1813	. 2 |- (A e. C -> A e. V)
7		elisset 1813	. 2 |- (B e. D -> B e. V)
8	5, 6, 7	syl2an 454	1 |- ((A e. C /\ B e. D) -> if(ph, A, B) e. {A, B})

Syntax hints:   -> wi 3   \/ wo 222   /\ wa 223   = wceq 954   e. wcel 956  Vcvv 1807  ifcif 2357  {cpr 2406

This theorem is referenced by:  suppr 4570

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 960  ax-gen 961  ax-8 962  ax-10 964  ax-12 966  ax-17 969  ax-4 971  ax-5o 973  ax-6o 976  ax-9o 1121  ax-10o 1138  ax-16 1208  ax-11o 1216  ax-ext 1457

This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225  df-ex 979  df-sb 1170  df-clab 1462  df-cleq 1467  df-clel 1470  df-v 1808  df-un 2046  df-if 2358  df-sn 2408  df-pr 2409

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