Theorem eqtr3 2100

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 2083	. 2 |- ( B = C <-> C = B )
2		eqtr 2098	. 2 |- ( ( A = C /\ C = B ) -> A = B )
3	1, 2	sylan2b 281	1 |- ( ( A = C /\ B = C ) -> A = B )

Syntax hints:   -> wi 4   /\ wa 102   = wceq 1284

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-5 1376  ax-gen 1378  ax-4 1440  ax-17 1459  ax-ext 2063

This theorem depends on definitions:  df-bi 115  df-cleq 2074

This theorem is referenced by:  eueq  2763  euind  2779  reuind  2795  preqsn  3567  eusv1  4202  funopg  4954  foco  5136  mpt2fun  5623  enq0tr  6624  lteupri  6807  elrealeu  6998  rereceu  7055  receuap  7759  xrltso  8871  xrlttri3  8872  odd2np1  10272