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Theorem 3eqtr4a 2098
Description: A chained equality inference, useful for converting to definitions. (Contributed by NM, 2-Feb-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.)
Hypotheses
Ref Expression
3eqtr4a.1  |-  A  =  B
3eqtr4a.2  |-  ( ph  ->  C  =  A )
3eqtr4a.3  |-  ( ph  ->  D  =  B )
Assertion
Ref Expression
3eqtr4a  |-  ( ph  ->  C  =  D )

Proof of Theorem 3eqtr4a
StepHypRef Expression
1 3eqtr4a.2 . . 3  |-  ( ph  ->  C  =  A )
2 3eqtr4a.1 . . 3  |-  A  =  B
31, 2syl6eq 2088 . 2  |-  ( ph  ->  C  =  B )
4 3eqtr4a.3 . 2  |-  ( ph  ->  D  =  B )
53, 4eqtr4d 2075 1  |-  ( ph  ->  C  =  D )
Colors of variables: wff set class
Syntax hints:    -> wi 4    = wceq 1243
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-5 1336  ax-gen 1338  ax-4 1400  ax-17 1419  ax-ext 2022
This theorem depends on definitions:  df-bi 110  df-cleq 2033
This theorem is referenced by:  uniintsnr  3651  fndmdifcom  5273  offres  5762  1stval2  5782  2ndval2  5783  ecovcom  6213  ecovass  6215  ecovdi  6217  zeo  8343  xnegneg  8746  fzsuc2  8941  expnegap0  9263  absexp  9675  sqr2irrlem  9877
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