Theorem onelssi 6426

Description: A member of an ordinal number is a subset of it. (Contributed by NM, 11-Aug-1994.)

Hypothesis

Ref	Expression
on.1	⊢ 𝐴 ∈ On

Assertion

Ref	Expression
onelssi	⊢ (𝐵 ∈ 𝐴 → 𝐵 ⊆ 𝐴)

Proof of Theorem onelssi

Step	Hyp	Ref	Expression
1		on.1	. 2 ⊢ 𝐴 ∈ On
2		onelss 6352	. 2 ⊢ (𝐴 ∈ On → (𝐵 ∈ 𝐴 → 𝐵 ⊆ 𝐴))
3	1, 2	ax-mp 5	1 ⊢ (𝐵 ∈ 𝐴 → 𝐵 ⊆ 𝐴)

Syntax hints:   → wi 4   ∈ wcel 2119   ⊆ wss 3883  Oncon0 6310

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1917  ax-6 1974  ax-7 2015  ax-8 2121  ax-9 2129  ax-ext 2711

This theorem depends on definitions:  df-bi 208  df-an 397  df-tru 1550  df-ex 1787  df-sb 2074  df-clab 2718  df-cleq 2731  df-clel 2814  df-ral 3054  df-v 3433  df-ss 3900  df-uni 4839  df-tr 5180  df-po 5526  df-so 5527  df-fr 5571  df-we 5573  df-ord 6313  df-on 6314

This theorem is referenced by:  onelini  6429  oneluni  6430  oawordeulem  8479  cardsdomelir  9888  carddom2  9892  cardaleph  10002  alephsing  10189  domtriomlem  10355  axdc3lem  10363  inar1  10689  nodense  27674