Theorem sseqtrrid 3293

Description: Subclass transitivity deduction. (Contributed by Jonathan Ben-Naim, 3-Jun-2011.)

Hypotheses

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

Assertion

Ref	Expression
sseqtrrid	⊢ (𝜑 → 𝐵 ⊆ 𝐶)

Proof of Theorem sseqtrrid

Step	Hyp	Ref	Expression
1		sseqtrrid.1	. . 3 ⊢ 𝐵 ⊆ 𝐴
2	1	a1i 9	. 2 ⊢ (𝜑 → 𝐵 ⊆ 𝐴)
3		sseqtrrid.2	. 2 ⊢ (𝜑 → 𝐶 = 𝐴)
4	2, 3	sseqtrrd 3281	1 ⊢ (𝜑 → 𝐵 ⊆ 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:  resdif  5641  fimacnv  5811  tfrlem5  6558  fsumsplit  12121  fprodsplitdc  12310  phimullem  12950  ennnfonelemss  13248  prdssca  14120  prdsbas  14121  prdsplusg  14122  prdsmulr  14123  lspssid  14677  istopon  15007  sscls  15114  mopnfss  15441  plyaddlem1  15741  plymullem1  15742  lgsquadlem2  16080