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Theorem 3anbi123d 1207
Description: Deduction joining 3 equivalences to form equivalence of conjunctions. (Contributed by NM, 22-Apr-1994.)
Hypotheses
Ref Expression
bi3d.1  |-  ( ph  ->  ( ps  <->  ch )
)
bi3d.2  |-  ( ph  ->  ( th  <->  ta )
)
bi3d.3  |-  ( ph  ->  ( et  <->  ze )
)
Assertion
Ref Expression
3anbi123d  |-  ( ph  ->  ( ( ps  /\  th 
/\  et )  <->  ( ch  /\ 
ta  /\  ze )
) )

Proof of Theorem 3anbi123d
StepHypRef Expression
1 bi3d.1 . . . 4  |-  ( ph  ->  ( ps  <->  ch )
)
2 bi3d.2 . . . 4  |-  ( ph  ->  ( th  <->  ta )
)
31, 2anbi12d 442 . . 3  |-  ( ph  ->  ( ( ps  /\  th )  <->  ( ch  /\  ta ) ) )
4 bi3d.3 . . 3  |-  ( ph  ->  ( et  <->  ze )
)
53, 4anbi12d 442 . 2  |-  ( ph  ->  ( ( ( ps 
/\  th )  /\  et ) 
<->  ( ( ch  /\  ta )  /\  ze )
) )
6 df-3an 887 . 2  |-  ( ( ps  /\  th  /\  et )  <->  ( ( ps 
/\  th )  /\  et ) )
7 df-3an 887 . 2  |-  ( ( ch  /\  ta  /\  ze )  <->  ( ( ch 
/\  ta )  /\  ze ) )
85, 6, 73bitr4g 212 1  |-  ( ph  ->  ( ( ps  /\  th 
/\  et )  <->  ( ch  /\ 
ta  /\  ze )
) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 97    <-> wb 98    /\ w3a 885
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  df-3an 887
This theorem is referenced by:  3anbi12d  1208  3anbi13d  1209  3anbi23d  1210  sbc3ang  2820  limeq  4114  smoeq  5905  tfrlemi1  5946  ereq1  6113  elinp  6572  iccshftr  8862  iccshftl  8864  iccdil  8866  icccntr  8868  fzaddel  8922  elfzomelpfzo  9087
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