Theorem sseqtrrdi 3291

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 2238	. 2 ⊢ 𝐵 = 𝐶
4	1, 3	sseqtrdi 3290	1 ⊢ (𝜑 → 𝐴 ⊆ 𝐶)

Syntax hints:   → wi 4   = wceq 1398   ⊆ wss 3214

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 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-11 1555  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-ext 2216

This theorem depends on definitions:  df-bi 117  df-nf 1510  df-sb 1812  df-clab 2221  df-cleq 2227  df-clel 2230  df-in 3220  df-ss 3227

This theorem is referenced by:  iunpw  4606  iotanul  5333  iotass  5335  tfrlem9  6563  tfrlemibfn  6572  tfrlemiubacc  6574  tfrlemi14d  6577  tfr1onlemssrecs  6583  tfr1onlemres  6593  tfrcllemres  6606  exmidfodomrlemr  7518  exmidfodomrlemrALT  7519  uznnssnn  9930  pfxccatpfx2  11457  shftfvalg  11531  shftfval  11534  clim2prod  12253  dvdsrvald  14341  dvdsrex  14346  eltopss  15003  difopn  15102  tgrest  15163  txuni2  15250  tgioo  15548  plycoeid3  15751