Theorem sseqtrrid 3291

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 3279	1 ⊢ (𝜑 → 𝐵 ⊆ 𝐶)

Syntax hints:   → wi 4   = wceq 1398   ⊆ wss 3213

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 3219  df-ss 3226

This theorem is referenced by:  resdif  5638  fimacnv  5808  tfrlem5  6547  fsumsplit  12101  fprodsplitdc  12290  phimullem  12930  ennnfonelemss  13182  prdssca  13509  prdsbas  13510  prdsplusg  13511  prdsmulr  13512  lspssid  14597  istopon  14927  sscls  15034  mopnfss  15361  plyaddlem1  15661  plymullem1  15662  lgsquadlem2  16000