Theorem syl5eqssr 3044

Description: B chained subclass and equality deduction. (Contributed by NM, 25-Apr-2004.)

Hypotheses

Ref	Expression
syl5eqssr.1	|- B = A
syl5eqssr.2	|- ( ph -> B C_ C )

Assertion

Ref	Expression
syl5eqssr	|- ( ph -> A C_ C )

Proof of Theorem syl5eqssr

Step	Hyp	Ref	Expression
1		syl5eqssr.1	. . 3 |- B = A
2	1	eqcomi 2085	. 2 |- A = B
3		syl5eqssr.2	. 2 |- ( ph -> B C_ C )
4	2, 3	syl5eqss 3043	1 |- ( ph -> A C_ C )

Syntax hints:   -> wi 4   = wceq 1284   C_ wss 2973

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-7 1377  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-8 1435  ax-11 1437  ax-4 1440  ax-17 1459  ax-i9 1463  ax-ial 1467  ax-i5r 1468  ax-ext 2063

This theorem depends on definitions:  df-bi 115  df-nf 1390  df-sb 1686  df-clab 2068  df-cleq 2074  df-clel 2077  df-in 2979  df-ss 2986

This theorem is referenced by:  relcnvtr  4860  resasplitss  5089  fimacnvdisj  5094  fimacnv  5317  f1ompt  5341