Theorem dflim6 43253

Description: A limit ordinal is a non-zero ordinal which is not a successor ordinal. Definition 1.11 of [Schloeder] p. 2. (Contributed by RP, 16-Jan-2025.)

Assertion

Ref	Expression
dflim6	⊢ (Lim 𝐴 ↔ (Ord 𝐴 ∧ 𝐴 ≠ ∅ ∧ ¬ ∃𝑏 ∈ On 𝐴 = suc 𝑏))

Distinct variable group:   𝐴,𝑏

Proof of Theorem dflim6

Step	Hyp	Ref	Expression
1		ioran 985	. . . 4 ⊢ (¬ (𝐴 = ∅ ∨ ∃𝑏 ∈ On 𝐴 = suc 𝑏) ↔ (¬ 𝐴 = ∅ ∧ ¬ ∃𝑏 ∈ On 𝐴 = suc 𝑏))
2		df-ne 2926	. . . . 5 ⊢ (𝐴 ≠ ∅ ↔ ¬ 𝐴 = ∅)
3	2	anbi1i 624	. . . 4 ⊢ ((𝐴 ≠ ∅ ∧ ¬ ∃𝑏 ∈ On 𝐴 = suc 𝑏) ↔ (¬ 𝐴 = ∅ ∧ ¬ ∃𝑏 ∈ On 𝐴 = suc 𝑏))
4	1, 3	bitr4i 278	. . 3 ⊢ (¬ (𝐴 = ∅ ∨ ∃𝑏 ∈ On 𝐴 = suc 𝑏) ↔ (𝐴 ≠ ∅ ∧ ¬ ∃𝑏 ∈ On 𝐴 = suc 𝑏))
5	4	anbi2i 623	. 2 ⊢ ((Ord 𝐴 ∧ ¬ (𝐴 = ∅ ∨ ∃𝑏 ∈ On 𝐴 = suc 𝑏)) ↔ (Ord 𝐴 ∧ (𝐴 ≠ ∅ ∧ ¬ ∃𝑏 ∈ On 𝐴 = suc 𝑏)))
6		dflim3 7823	. 2 ⊢ (Lim 𝐴 ↔ (Ord 𝐴 ∧ ¬ (𝐴 = ∅ ∨ ∃𝑏 ∈ On 𝐴 = suc 𝑏)))
7		3anass 1094	. 2 ⊢ ((Ord 𝐴 ∧ 𝐴 ≠ ∅ ∧ ¬ ∃𝑏 ∈ On 𝐴 = suc 𝑏) ↔ (Ord 𝐴 ∧ (𝐴 ≠ ∅ ∧ ¬ ∃𝑏 ∈ On 𝐴 = suc 𝑏)))
8	5, 6, 7	3bitr4i 303	1 ⊢ (Lim 𝐴 ↔ (Ord 𝐴 ∧ 𝐴 ≠ ∅ ∧ ¬ ∃𝑏 ∈ On 𝐴 = suc 𝑏))

Syntax hints:  ¬ wn 3   ↔ wb 206   ∧ wa 395   ∨ wo 847   ∧ w3a 1086   = wceq 1540   ≠ wne 2925  ∃wrex 3053  ∅c0 4296  Ord word 6331  Oncon0 6332  Lim wlim 6333  suc csuc 6334

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-ext 2701  ax-sep 5251  ax-nul 5261  ax-pr 5387  ax-un 7711

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3or 1087  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1780  df-sb 2066  df-clab 2708  df-cleq 2721  df-clel 2803  df-ne 2926  df-ral 3045  df-rex 3054  df-rab 3406  df-v 3449  df-dif 3917  df-un 3919  df-in 3921  df-ss 3931  df-pss 3934  df-nul 4297  df-if 4489  df-pw 4565  df-sn 4590  df-pr 4592  df-op 4596  df-uni 4872  df-br 5108  df-opab 5170  df-tr 5215  df-eprel 5538  df-po 5546  df-so 5547  df-fr 5591  df-we 5593  df-ord 6335  df-on 6336  df-lim 6337  df-suc 6338

This theorem is referenced by:  limnsuc  43254