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Theorem 3eqtr3g 2137
Description: A chained equality inference, useful for converting from definitions. (Contributed by NM, 15-Nov-1994.)
Hypotheses
Ref Expression
3eqtr3g.1  |-  ( ph  ->  A  =  B )
3eqtr3g.2  |-  A  =  C
3eqtr3g.3  |-  B  =  D
Assertion
Ref Expression
3eqtr3g  |-  ( ph  ->  C  =  D )

Proof of Theorem 3eqtr3g
StepHypRef Expression
1 3eqtr3g.2 . . 3  |-  A  =  C
2 3eqtr3g.1 . . 3  |-  ( ph  ->  A  =  B )
31, 2syl5eqr 2128 . 2  |-  ( ph  ->  C  =  B )
4 3eqtr3g.3 . 2  |-  B  =  D
53, 4syl6eq 2130 1  |-  ( ph  ->  C  =  D )
Colors of variables: wff set class
Syntax hints:    -> wi 4    = wceq 1285
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-5 1377  ax-gen 1379  ax-4 1441  ax-17 1460  ax-ext 2064
This theorem depends on definitions:  df-bi 115  df-cleq 2075
This theorem is referenced by:  csbnest1g  2958  dfopg  3576  cores2  4863  funcoeqres  5188  dftpos2  5910  ine0  7565
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