Theorem eqtr3 2190

Description: A transitive law for class equality. (Contributed by NM, 20-May-2005.)

Assertion

Ref	Expression
eqtr3	|- ( ( A = C /\ B = C ) -> A = B )

Proof of Theorem eqtr3

Step	Hyp	Ref	Expression
1		eqcom 2172	. 2 |- ( B = C <-> C = B )
2		eqtr 2188	. 2 |- ( ( A = C /\ C = B ) -> A = B )
3	1, 2	sylan2b 285	1 |- ( ( A = C /\ B = C ) -> A = B )

Syntax hints:   -> wi 4   /\ wa 103   = wceq 1348

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 1440  ax-gen 1442  ax-4 1503  ax-17 1519  ax-ext 2152

This theorem depends on definitions:  df-bi 116  df-cleq 2163

This theorem is referenced by:  eueq  2901  euind  2917  reuind  2935  preqsn  3762  eusv1  4437  funopg  5232  funinsn  5247  foco  5430  mpofun  5955  enq0tr  7396  lteupri  7579  elrealeu  7791  rereceu  7851  receuap  8587  xrltso  9753  xrlttri3  9754  iseqf1olemab  10445  fsumparts  11433  odd2np1  11832  grpinveu  12741  exmidsbthrlem  14054