Theorem eqtr2id 2284

Description: An equality transitivity deduction. (Contributed by NM, 29-Mar-1998.)

Hypotheses

Ref	Expression
eqtr2id.1	|- A = B
eqtr2id.2	|- ( ph -> B = C )

Assertion

Ref	Expression
eqtr2id	|- ( ph -> C = A )

Proof of Theorem eqtr2id

Step	Hyp	Ref	Expression
1		eqtr2id.1	. . 3 |- A = B
2		eqtr2id.2	. . 3 |- ( ph -> B = C )
3	1, 2	eqtrid 2283	. 2 |- ( ph -> A = C )
4	3	eqcomd 2244	1 |- ( ph -> C = A )

Syntax hints:   -> wi 4   = wceq 1402

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 1500  ax-gen 1502  ax-4 1563  ax-17 1579  ax-ext 2220

This theorem depends on definitions:  df-bi 117  df-cleq 2231

This theorem is referenced by:  eqtr3di  2286  opeqsn  4388  dcextest  4723  relop  4925  funopg  5406  funcnvres  5449  mapsnconst  6966  snexxph  7257  apreap  8905  recextlem1  8969  nn0supp  9598  intqfrac2  10734  hashprg  11227  hashfacen  11262  ccatrid  11353  explecnv  12250  grp1inv  13889  rnrhmsubrg  14533  rerestcntop  15582  rerest  15584  mpomulcn  15590  binom4  16004  wlkvtxedg  16518  wlkres  16534