Theorem ifel 3698

Description: Membership of a conditional operator. (Contributed by NM, 10-Sep-2005.)

Assertion

Ref	Expression
ifel	|- (if(ph, A, B) e. C <-> ((ph /\ A e. C) \/ (-. ph /\ B e. C)))

Proof of Theorem ifel

Step	Hyp	Ref	Expression
1		eleq1 2413	. 2 |- (if(ph, A, B) = A -> (if(ph, A, B) e. C <-> A e. C))
2		eleq1 2413	. 2 |- (if(ph, A, B) = B -> (if(ph, A, B) e. C <-> B e. C))
3	1, 2	elimif 3692	1 |- (if(ph, A, B) e. C <-> ((ph /\ A e. C) \/ (-. ph /\ B e. C)))

Syntax hints:  -. wn 3   <-> wb 176   \/ wo 357   /\ wa 358   e. wcel 1710  ifcif 3663

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-if 3664

This theorem is referenced by: (None)