Theorem syl6eqss 2995

Description: A chained subclass and equality deduction. (Contributed by Mario Carneiro, 2-Jan-2017.)

Hypotheses

Ref	Expression
syl6eqss.1	|- ( ph -> A = B )
syl6eqss.2	|- B C_ C

Assertion

Ref	Expression
syl6eqss	|- ( ph -> A C_ C )

Proof of Theorem syl6eqss

Step	Hyp	Ref	Expression
1		syl6eqss.1	. 2 |- ( ph -> A = B )
2		syl6eqss.2	. . 3 |- B C_ C
3	2	a1i 9	. 2 |- ( ph -> B C_ C )
4	1, 3	eqsstrd 2979	1 |- ( ph -> A C_ C )

Syntax hints:   -> wi 4   = wceq 1243   C_ wss 2917

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-11 1397  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022

This theorem depends on definitions:  df-bi 110  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-in 2924  df-ss 2931

This theorem is referenced by:  syl6eqssr  2996  resasplitss  5069  fimacnv  5296  bj-nntrans  10076