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Theorem ifbieq12i 3497
Description: Equivalence deduction for conditional operators. (Contributed by NM, 18-Mar-2013.)
Hypotheses
Ref Expression
ifbieq12i.1  |-  ( ph  <->  ps )
ifbieq12i.2  |-  A  =  C
ifbieq12i.3  |-  B  =  D
Assertion
Ref Expression
ifbieq12i  |-  if (
ph ,  A ,  B )  =  if ( ps ,  C ,  D )

Proof of Theorem ifbieq12i
StepHypRef Expression
1 ifbieq12i.2 . . 3  |-  A  =  C
2 ifeq1 3477 . . 3  |-  ( A  =  C  ->  if ( ph ,  A ,  B )  =  if ( ph ,  C ,  B ) )
31, 2ax-mp 5 . 2  |-  if (
ph ,  A ,  B )  =  if ( ph ,  C ,  B )
4 ifbieq12i.1 . . 3  |-  ( ph  <->  ps )
5 ifbieq12i.3 . . 3  |-  B  =  D
64, 5ifbieq2i 3495 . 2  |-  if (
ph ,  C ,  B )  =  if ( ps ,  C ,  D )
73, 6eqtri 2160 1  |-  if (
ph ,  A ,  B )  =  if ( ps ,  C ,  D )
Colors of variables: wff set class
Syntax hints:    <-> wb 104    = wceq 1331   ifcif 3474
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 603  ax-in2 604  ax-io 698  ax-5 1423  ax-7 1424  ax-gen 1425  ax-ie1 1469  ax-ie2 1470  ax-8 1482  ax-10 1483  ax-11 1484  ax-i12 1485  ax-bndl 1486  ax-4 1487  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-ext 2121
This theorem depends on definitions:  df-bi 116  df-tru 1334  df-nf 1437  df-sb 1736  df-clab 2126  df-cleq 2132  df-clel 2135  df-nfc 2270  df-rab 2425  df-v 2688  df-un 3075  df-if 3475
This theorem is referenced by: (None)
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