Theorem sseqtrrdi 3297

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

Hypotheses

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

Assertion

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

Proof of Theorem sseqtrrdi

Step	Hyp	Ref	Expression
1		sseqtrrdi.1	. 2 |- ( ph -> A C_ B )
2		sseqtrrdi.2	. . 3 |- C = B
3	2	eqcomi 2242	. 2 |- B = C
4	1, 3	sseqtrdi 3296	1 |- ( ph -> A C_ C )

This proof depends on syntax axioms:   -> wi 4   = wceq 1402   C_ wss 3220

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-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-8 1557  ax-11 1559  ax-4 1563  ax-17 1579  ax-i9 1583  ax-ial 1587  ax-i5r 1588  ax-ext 2220

This proof depends on definitions:  df-bi 117  df-nf 1514  df-sb 1816  df-clab 2225  df-cleq 2231  df-clel 2234  df-in 3226  df-ss 3233

This theorem is used by:  iunpw  4626  iotanul  5353  iotass  5355  tfrlem9  6590  tfrlemibfn  6599  tfrlemiubacc  6601  tfrlemi14d  6604  tfr1onlemssrecs  6610  tfr1onlemres  6620  tfrcllemres  6633  exmidfodomrlemr  7555  exmidfodomrlemrALT  7556  uznnssnn  9987  pfxccatpfx2  11525  shftfvalg  11599  shftfval  11602  clim2prod  12325  dvdsrvald  14484  dvdsrex  14489  eltopss  15201  difopn  15300  tgrest  15361  txuni2  15448  tgioo  15746  plycoeid3  15949