Theorem onss 4584

Description: An ordinal number is a subset of the class of ordinal numbers. (Contributed by NM, 5-Jun-1994.)

Assertion

Ref	Expression
onss	⊢ (𝐴 ∈ On → 𝐴 ⊆ On)

Proof of Theorem onss

Step	Hyp	Ref	Expression
1		eloni 4465	. 2 ⊢ (𝐴 ∈ On → Ord 𝐴)
2		ordsson 4583	. 2 ⊢ (Ord 𝐴 → 𝐴 ⊆ On)
3	1, 2	syl 14	1 ⊢ (𝐴 ∈ On → 𝐴 ⊆ On)

Syntax hints:   → wi 4   ∈ wcel 2200   ⊆ wss 3197  Ord word 4452  Oncon0 4453

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-io 714  ax-5 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-10 1551  ax-11 1552  ax-i12 1553  ax-bndl 1555  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-ext 2211

This theorem depends on definitions:  df-bi 117  df-3an 1004  df-tru 1398  df-nf 1507  df-sb 1809  df-clab 2216  df-cleq 2222  df-clel 2225  df-nfc 2361  df-ral 2513  df-rex 2514  df-v 2801  df-in 3203  df-ss 3210  df-uni 3888  df-tr 4182  df-iord 4456  df-on 4458

This theorem is referenced by:  onuni  4585  onssi  4606  tfrexlem  6478  tfri3  6511  rdgivallem  6525  bj-omssonALT  16284