Theorem sselii 2996

Description: Membership inference from subclass relationship. (Contributed by NM, 31-May-1999.)

Hypotheses

Ref	Expression
sseli.1	⊢ 𝐴 ⊆ 𝐵
sselii.2	⊢ 𝐶 ∈ 𝐴

Assertion

Ref	Expression
sselii	⊢ 𝐶 ∈ 𝐵

Proof of Theorem sselii

Step	Hyp	Ref	Expression
1		sselii.2	. 2 ⊢ 𝐶 ∈ 𝐴
2		sseli.1	. . 3 ⊢ 𝐴 ⊆ 𝐵
3	2	sseli 2995	. 2 ⊢ (𝐶 ∈ 𝐴 → 𝐶 ∈ 𝐵)
4	1, 3	ax-mp 7	1 ⊢ 𝐶 ∈ 𝐵

Syntax hints:   ∈ wcel 1433   ⊆ wss 2973

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-5 1376  ax-7 1377  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-8 1435  ax-11 1437  ax-4 1440  ax-17 1459  ax-i9 1463  ax-ial 1467  ax-i5r 1468  ax-ext 2063

This theorem depends on definitions:  df-bi 115  df-nf 1390  df-sb 1686  df-clab 2068  df-cleq 2074  df-clel 2077  df-in 2979  df-ss 2986

This theorem is referenced by:  brtpos0  5890  ax1cn  7029  recni  7131  0xr  7165  nn0rei  8299  nnzi  8372  nn0zi  8373  pnfxr  8846