Theorem eqtr3 2213

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 2195	. 2 |- ( B = C <-> C = B )
2		eqtr 2211	. 2 |- ( ( A = C /\ C = B ) -> A = B )
3	1, 2	sylan2b 287	1 |- ( ( A = C /\ B = C ) -> A = B )

Syntax hints:   -> wi 4   /\ wa 104   = wceq 1364

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 1458  ax-gen 1460  ax-4 1521  ax-17 1537  ax-ext 2175

This theorem depends on definitions:  df-bi 117  df-cleq 2186

This theorem is referenced by:  eueq  2932  euind  2948  reuind  2966  preqsn  3802  eusv1  4484  funopg  5289  funinsn  5304  foco  5488  mpofun  6021  enq0tr  7496  lteupri  7679  elrealeu  7891  rereceu  7951  receuap  8690  xrltso  9865  xrlttri3  9866  iseqf1olemab  10576  fsumparts  11616  odd2np1  12017  grpinveu  13113  exmidsbthrlem  15582