Theorem 3eqtr3a 2223

Description: A chained equality inference, useful for converting from definitions. (Contributed by Mario Carneiro, 6-Nov-2015.)

Hypotheses

Ref	Expression
3eqtr3a.1	|- A = B
3eqtr3a.2	|- ( ph -> A = C )
3eqtr3a.3	|- ( ph -> B = D )

Assertion

Ref	Expression
3eqtr3a	|- ( ph -> C = D )

Proof of Theorem 3eqtr3a

Step	Hyp	Ref	Expression
1		3eqtr3a.2	. 2 |- ( ph -> A = C )
2		3eqtr3a.1	. . 3 |- A = B
3		3eqtr3a.3	. . 3 |- ( ph -> B = D )
4	2, 3	syl5eq 2211	. 2 |- ( ph -> A = D )
5	1, 4	eqtr3d 2200	1 |- ( ph -> C = D )

Syntax hints:   -> wi 4   = wceq 1343

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-5 1435  ax-gen 1437  ax-4 1498  ax-17 1514  ax-ext 2147

This theorem depends on definitions:  df-bi 116  df-cleq 2158

This theorem is referenced by:  uneqin  3373  coi2  5120  foima  5415  f1imacnv  5449  fvsnun2  5683  fnsnsplitdc  6473  phplem4  6821  phplem4on  6833  halfnqq  7351  resqrexlemcalc1  10956  absefib  11711  efieq1re  11712  restopnb  12821  cnmpt2t  12933  reeflog  13424  rpcxpsqrt  13482