Theorem 3eqtr3ri 2268

Description: An inference from three chained equalities. (Contributed by NM, 15-Aug-2004.)

Hypotheses

Ref	Expression
3eqtr3i.1	|- A = B
3eqtr3i.2	|- A = C
3eqtr3i.3	|- B = D

Assertion

Ref	Expression
3eqtr3ri	|- D = C

Proof of Theorem 3eqtr3ri

Step	Hyp	Ref	Expression
1		3eqtr3i.3	. 2 |- B = D
2		3eqtr3i.1	. . 3 |- A = B
3		3eqtr3i.2	. . 3 |- A = C
4	2, 3	eqtr3i 2261	. 2 |- B = C
5	1, 4	eqtr3i 2261	1 |- D = C

This proof depends on syntax axioms:   = wceq 1402

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

This theorem is used by:  indif2  3475  resdm2  5278  co01  5302  cocnvres  5312  undifdc  7231  1mhlfehlf  9527  rei  11679  resqrexlemover  11790  cos1bnd  12542  m1bits  12743  6gcd4e2  12788  3lcm2e6  12955  karatsuba  13230  ballotfilemth  13330  cosq23lt0  15984  sincos4thpi  15991  sincos6thpi  15993  cosq34lt1  16001  bclbnd  16205