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Theorem bi2bian9 540
Description: Deduction joining two biconditionals with different antecedents. (Contributed by NM, 12-May-2004.)
Hypotheses
Ref Expression
bi2an9.1  |-  ( ph  ->  ( ps  <->  ch )
)
bi2an9.2  |-  ( th 
->  ( ta  <->  et )
)
Assertion
Ref Expression
bi2bian9  |-  ( (
ph  /\  th )  ->  ( ( ps  <->  ta )  <->  ( ch  <->  et ) ) )

Proof of Theorem bi2bian9
StepHypRef Expression
1 bi2an9.1 . . 3  |-  ( ph  ->  ( ps  <->  ch )
)
21adantr 261 . 2  |-  ( (
ph  /\  th )  ->  ( ps  <->  ch )
)
3 bi2an9.2 . . 3  |-  ( th 
->  ( ta  <->  et )
)
43adantl 262 . 2  |-  ( (
ph  /\  th )  ->  ( ta  <->  et )
)
52, 4bibi12d 224 1  |-  ( (
ph  /\  th )  ->  ( ( ps  <->  ta )  <->  ( ch  <->  et ) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 97    <-> wb 98
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101
This theorem depends on definitions:  df-bi 110
This theorem is referenced by: (None)
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