Theorem 3eqtr3g 2249

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 2240	. 2 |- ( ph -> C = B )
4		3eqtr3g.3	. 2 |- B = D
5	3, 4	eqtrdi 2242	1 |- ( ph -> C = D )

Syntax hints:   -> wi 4   = wceq 1364

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 1458  ax-gen 1460  ax-4 1521  ax-17 1537  ax-ext 2175

This theorem depends on definitions:  df-bi 117  df-cleq 2186

This theorem is referenced by:  csbnest1g  3137  disjdif2  3526  dfopg  3803  xpid11  4886  sqxpeq0  5090  cores2  5179  funcoeqres  5532  dftpos2  6316  ine0  8415  fisumcom2  11584  fisum0diag2  11593  mertenslemi1  11681  fprodcom2fi  11772  fprodmodd  11787  4sqlem10  12528  setsslnid  12673  xpsff1o  12935  eqglact  13298  oppr1g  13581  dvmptccn  14894  dvmptc  14896  dvmptfsum  14904  nninffeq  15580