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Theorem dedth3h 3746
Description: Weak deduction theorem eliminating three hypotheses. See comments in dedth2h 3745. (Contributed by NM, 15-May-1999.)
Hypotheses
Ref Expression
dedth3h.1  |-  ( A  =  if ( ph ,  A ,  D )  ->  ( th  <->  ta )
)
dedth3h.2  |-  ( B  =  if ( ps ,  B ,  R
)  ->  ( ta  <->  et ) )
dedth3h.3  |-  ( C  =  if ( ch ,  C ,  S
)  ->  ( et  <->  ze ) )
dedth3h.4  |-  ze
Assertion
Ref Expression
dedth3h  |-  ( (
ph  /\  ps  /\  ch )  ->  th )

Proof of Theorem dedth3h
StepHypRef Expression
1 dedth3h.1 . . . 4  |-  ( A  =  if ( ph ,  A ,  D )  ->  ( th  <->  ta )
)
21imbi2d 308 . . 3  |-  ( A  =  if ( ph ,  A ,  D )  ->  ( ( ( ps  /\  ch )  ->  th )  <->  ( ( ps  /\  ch )  ->  ta ) ) )
3 dedth3h.2 . . . 4  |-  ( B  =  if ( ps ,  B ,  R
)  ->  ( ta  <->  et ) )
4 dedth3h.3 . . . 4  |-  ( C  =  if ( ch ,  C ,  S
)  ->  ( et  <->  ze ) )
5 dedth3h.4 . . . 4  |-  ze
63, 4, 5dedth2h 3745 . . 3  |-  ( ( ps  /\  ch )  ->  ta )
72, 6dedth 3744 . 2  |-  ( ph  ->  ( ( ps  /\  ch )  ->  th )
)
873impib 1151 1  |-  ( (
ph  /\  ps  /\  ch )  ->  th )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 177    /\ wa 359    /\ w3a 936    = wceq 1649   ifcif 3703
This theorem is referenced by:  dedth3v  3749  faclbnd4lem2  11544  dvdsle  12854  gcdaddm  12988  ipdiri  22288  hvaddcan  22529  hvsubadd  22536  norm3dif  22609  omlsii  22862  chjass  22992  ledi  22999  spansncv  23112  pjcjt2  23151  pjopyth  23179  hoaddass  23242  hocsubdir  23245  hoddi  23450
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1552  ax-5 1563  ax-17 1623  ax-9 1662  ax-8 1683  ax-6 1740  ax-7 1745  ax-11 1757  ax-12 1946  ax-ext 2389
This theorem depends on definitions:  df-bi 178  df-or 360  df-an 361  df-3an 938  df-tru 1325  df-ex 1548  df-nf 1551  df-sb 1656  df-clab 2395  df-cleq 2401  df-clel 2404  df-if 3704
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