Theorem 3eqtr3g 2287

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

Step	Hyp	Ref	Expression
1		3eqtr3g.2	. . 3 |- A = C
2		3eqtr3g.1	. . 3 |- ( ph -> A = B )
3	1, 2	eqtr3id 2278	. 2 |- ( ph -> C = B )
4		3eqtr3g.3	. 2 |- B = D
5	3, 4	eqtrdi 2280	1 |- ( ph -> C = D )

Syntax hints:   -> wi 4   = wceq 1398

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1496  ax-gen 1498  ax-4 1559  ax-17 1575  ax-ext 2213

This theorem depends on definitions:  df-bi 117  df-cleq 2224

This theorem is referenced by:  csbnest1g  3184  disjdif2  3575  dfopg  3865  xpid11  4961  sqxpeq0  5167  cores2  5256  funcoeqres  5623  dftpos2  6470  ine0  8632  fisumcom2  12079  fisum0diag2  12088  mertenslemi1  12176  fprodcom2fi  12267  fprodmodd  12282  bitsinv1  12603  4sqlem10  13040  setsslnid  13214  xpsff1o  13512  eqglact  13892  oppr1g  14176  dvmptccn  15526  dvmptc  15528  dvmptfsum  15536  fsumdvdsmul  15805  nninffeq  16746