Theorem ordsucuni 7856

Description: An ordinal class is a subclass of the successor of its union. (Contributed by NM, 12-Sep-2003.)

Assertion

Ref	Expression
ordsucuni	⊢ (Ord 𝐴 → 𝐴 ⊆ suc ∪ 𝐴)

Proof of Theorem ordsucuni

Step	Hyp	Ref	Expression
1		ordsson 7809	. 2 ⊢ (Ord 𝐴 → 𝐴 ⊆ On)
2		onsucuni 7855	. 2 ⊢ (𝐴 ⊆ On → 𝐴 ⊆ suc ∪ 𝐴)
3	1, 2	syl 17	1 ⊢ (Ord 𝐴 → 𝐴 ⊆ suc ∪ 𝐴)

Syntax hints:   → wi 4   ⊆ wss 3966  ∪ cuni 4915  Ord word 6391  Oncon0 6392  suc csuc 6394

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1794  ax-4 1808  ax-5 1910  ax-6 1967  ax-7 2007  ax-8 2110  ax-9 2118  ax-ext 2708  ax-sep 5305  ax-nul 5315  ax-pr 5441

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 849  df-3or 1088  df-3an 1089  df-tru 1542  df-fal 1552  df-ex 1779  df-sb 2065  df-clab 2715  df-cleq 2729  df-clel 2816  df-ne 2941  df-ral 3062  df-rex 3071  df-rab 3437  df-v 3483  df-dif 3969  df-un 3971  df-in 3973  df-ss 3983  df-pss 3986  df-nul 4343  df-if 4535  df-pw 4610  df-sn 4635  df-pr 4637  df-op 4641  df-uni 4916  df-br 5152  df-opab 5214  df-tr 5269  df-eprel 5593  df-po 5601  df-so 5602  df-fr 5645  df-we 5647  df-ord 6395  df-on 6396  df-suc 6398

This theorem is referenced by:  orduniorsuc  7857