Theorem eqtr3 2185

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 2167	. 2 |- ( B = C <-> C = B )
2		eqtr 2183	. 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 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:  eueq  2897  euind  2913  reuind  2931  preqsn  3755  eusv1  4430  funopg  5222  funinsn  5237  foco  5420  mpofun  5944  enq0tr  7375  lteupri  7558  elrealeu  7770  rereceu  7830  receuap  8566  xrltso  9732  xrlttri3  9733  iseqf1olemab  10424  fsumparts  11411  odd2np1  11810  exmidsbthrlem  13901