Theorem sseqtrrdi 3273

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

Hypotheses

Ref	Expression
sseqtrrdi.1	⊢ (𝜑 → 𝐴 ⊆ 𝐵)
sseqtrrdi.2	⊢ 𝐶 = 𝐵

Assertion

Ref	Expression
sseqtrrdi	⊢ (𝜑 → 𝐴 ⊆ 𝐶)

Proof of Theorem sseqtrrdi

Step	Hyp	Ref	Expression
1		sseqtrrdi.1	. 2 ⊢ (𝜑 → 𝐴 ⊆ 𝐵)
2		sseqtrrdi.2	. . 3 ⊢ 𝐶 = 𝐵
3	2	eqcomi 2233	. 2 ⊢ 𝐵 = 𝐶
4	1, 3	sseqtrdi 3272	1 ⊢ (𝜑 → 𝐴 ⊆ 𝐶)

Syntax hints:   → wi 4   = wceq 1395   ⊆ wss 3197

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 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-11 1552  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-ext 2211

This theorem depends on definitions:  df-bi 117  df-nf 1507  df-sb 1809  df-clab 2216  df-cleq 2222  df-clel 2225  df-in 3203  df-ss 3210

This theorem is referenced by:  iunpw  4572  iotanul  5297  iotass  5299  tfrlem9  6476  tfrlemibfn  6485  tfrlemiubacc  6487  tfrlemi14d  6490  tfr1onlemssrecs  6496  tfr1onlemres  6506  tfrcllemres  6519  exmidfodomrlemr  7396  exmidfodomrlemrALT  7397  uznnssnn  9789  pfxccatpfx2  11290  shftfvalg  11350  shftfval  11353  clim2prod  12071  dvdsrvald  14078  dvdsrex  14083  eltopss  14704  difopn  14803  tgrest  14864  txuni2  14951  tgioo  15249  plycoeid3  15452