Theorem bnj168 30052

Description: First-order logic and set theory. Revised to remove dependence on ax-reg 8380. (Contributed by Jonathan Ben-Naim, 3-Jun-2011.) (Revised by NM, 21-Dec-2016.) (New usage is discouraged.)

Hypothesis

Ref	Expression
bnj168.1	⊢ 𝐷 = (ω ∖ {∅})

Assertion

Ref	Expression
bnj168	⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 ∈ 𝐷) → ∃𝑚 ∈ 𝐷 𝑛 = suc 𝑚)

Distinct variable group:   𝑚,𝑛

Allowed substitution hints:   𝐷(𝑚,𝑛)

Proof of Theorem bnj168

Step	Hyp	Ref	Expression
1		bnj168.1	. . . . . . . . . 10 ⊢ 𝐷 = (ω ∖ {∅})
2	1	bnj158 30051	. . . . . . . . 9 ⊢ (𝑛 ∈ 𝐷 → ∃𝑚 ∈ ω 𝑛 = suc 𝑚)
3	2	anim2i 591	. . . . . . . 8 ⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 ∈ 𝐷) → (𝑛 ≠ 1𝑜 ∧ ∃𝑚 ∈ ω 𝑛 = suc 𝑚))
4		r19.42v 3073	. . . . . . . 8 ⊢ (∃𝑚 ∈ ω (𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) ↔ (𝑛 ≠ 1𝑜 ∧ ∃𝑚 ∈ ω 𝑛 = suc 𝑚))
5	3, 4	sylibr 223	. . . . . . 7 ⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 ∈ 𝐷) → ∃𝑚 ∈ ω (𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚))
6		neeq1 2844	. . . . . . . . . . 11 ⊢ (𝑛 = suc 𝑚 → (𝑛 ≠ 1𝑜 ↔ suc 𝑚 ≠ 1𝑜))
7	6	biimpac 502	. . . . . . . . . 10 ⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) → suc 𝑚 ≠ 1𝑜)
8		df-1o 7447	. . . . . . . . . . . . 13 ⊢ 1𝑜 = suc ∅
9	8	eqeq2i 2622	. . . . . . . . . . . 12 ⊢ (suc 𝑚 = 1𝑜 ↔ suc 𝑚 = suc ∅)
10		nnon 6963	. . . . . . . . . . . . 13 ⊢ (𝑚 ∈ ω → 𝑚 ∈ On)
11		0elon 5695	. . . . . . . . . . . . 13 ⊢ ∅ ∈ On
12		suc11 5748	. . . . . . . . . . . . 13 ⊢ ((𝑚 ∈ On ∧ ∅ ∈ On) → (suc 𝑚 = suc ∅ ↔ 𝑚 = ∅))
13	10, 11, 12	sylancl 693	. . . . . . . . . . . 12 ⊢ (𝑚 ∈ ω → (suc 𝑚 = suc ∅ ↔ 𝑚 = ∅))
14	9, 13	syl5rbb 272	. . . . . . . . . . 11 ⊢ (𝑚 ∈ ω → (𝑚 = ∅ ↔ suc 𝑚 = 1𝑜))
15	14	necon3bid 2826	. . . . . . . . . 10 ⊢ (𝑚 ∈ ω → (𝑚 ≠ ∅ ↔ suc 𝑚 ≠ 1𝑜))
16	7, 15	syl5ibr 235	. . . . . . . . 9 ⊢ (𝑚 ∈ ω → ((𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) → 𝑚 ≠ ∅))
17	16	ancld 574	. . . . . . . 8 ⊢ (𝑚 ∈ ω → ((𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) → ((𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) ∧ 𝑚 ≠ ∅)))
18	17	reximia 2992	. . . . . . 7 ⊢ (∃𝑚 ∈ ω (𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) → ∃𝑚 ∈ ω ((𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) ∧ 𝑚 ≠ ∅))
19	5, 18	syl 17	. . . . . 6 ⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 ∈ 𝐷) → ∃𝑚 ∈ ω ((𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) ∧ 𝑚 ≠ ∅))
20		anass 679	. . . . . . 7 ⊢ (((𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) ∧ 𝑚 ≠ ∅) ↔ (𝑛 ≠ 1𝑜 ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)))
21	20	rexbii 3023	. . . . . 6 ⊢ (∃𝑚 ∈ ω ((𝑛 ≠ 1𝑜 ∧ 𝑛 = suc 𝑚) ∧ 𝑚 ≠ ∅) ↔ ∃𝑚 ∈ ω (𝑛 ≠ 1𝑜 ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)))
22	19, 21	sylib 207	. . . . 5 ⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 ∈ 𝐷) → ∃𝑚 ∈ ω (𝑛 ≠ 1𝑜 ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)))
23		simpr 476	. . . . 5 ⊢ ((𝑛 ≠ 1𝑜 ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)) → (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅))
24	22, 23	bnj31 30039	. . . 4 ⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 ∈ 𝐷) → ∃𝑚 ∈ ω (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅))
25		df-rex 2902	. . . 4 ⊢ (∃𝑚 ∈ ω (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅) ↔ ∃𝑚(𝑚 ∈ ω ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)))
26	24, 25	sylib 207	. . 3 ⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 ∈ 𝐷) → ∃𝑚(𝑚 ∈ ω ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)))
27		simpr 476	. . . . . . 7 ⊢ ((𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅) → 𝑚 ≠ ∅)
28	27	anim2i 591	. . . . . 6 ⊢ ((𝑚 ∈ ω ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)) → (𝑚 ∈ ω ∧ 𝑚 ≠ ∅))
29	1	eleq2i 2680	. . . . . . 7 ⊢ (𝑚 ∈ 𝐷 ↔ 𝑚 ∈ (ω ∖ {∅}))
30		eldifsn 4260	. . . . . . 7 ⊢ (𝑚 ∈ (ω ∖ {∅}) ↔ (𝑚 ∈ ω ∧ 𝑚 ≠ ∅))
31	29, 30	bitr2i 264	. . . . . 6 ⊢ ((𝑚 ∈ ω ∧ 𝑚 ≠ ∅) ↔ 𝑚 ∈ 𝐷)
32	28, 31	sylib 207	. . . . 5 ⊢ ((𝑚 ∈ ω ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)) → 𝑚 ∈ 𝐷)
33		simprl 790	. . . . 5 ⊢ ((𝑚 ∈ ω ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)) → 𝑛 = suc 𝑚)
34	32, 33	jca 553	. . . 4 ⊢ ((𝑚 ∈ ω ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)) → (𝑚 ∈ 𝐷 ∧ 𝑛 = suc 𝑚))
35	34	eximi 1752	. . 3 ⊢ (∃𝑚(𝑚 ∈ ω ∧ (𝑛 = suc 𝑚 ∧ 𝑚 ≠ ∅)) → ∃𝑚(𝑚 ∈ 𝐷 ∧ 𝑛 = suc 𝑚))
36	26, 35	syl 17	. 2 ⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 ∈ 𝐷) → ∃𝑚(𝑚 ∈ 𝐷 ∧ 𝑛 = suc 𝑚))
37		df-rex 2902	. 2 ⊢ (∃𝑚 ∈ 𝐷 𝑛 = suc 𝑚 ↔ ∃𝑚(𝑚 ∈ 𝐷 ∧ 𝑛 = suc 𝑚))
38	36, 37	sylibr 223	1 ⊢ ((𝑛 ≠ 1𝑜 ∧ 𝑛 ∈ 𝐷) → ∃𝑚 ∈ 𝐷 𝑛 = suc 𝑚)

Syntax hints:   → wi 4   ↔ wb 195   ∧ wa 383   = wceq 1475  ∃wex 1695   ∈ wcel 1977   ≠ wne 2780  ∃wrex 2897   ∖ cdif 3537  ∅c0 3874  {csn 4125  Oncon0 5640  suc csuc 5642  ωcom 6957  1_𝑜c1o 7440

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-8 1979  ax-9 1986  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590  ax-sep 4709  ax-nul 4717  ax-pr 4833  ax-un 6847

This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-3or 1032  df-3an 1033  df-tru 1478  df-ex 1696  df-nf 1701  df-sb 1868  df-eu 2462  df-mo 2463  df-clab 2597  df-cleq 2603  df-clel 2606  df-nfc 2740  df-ne 2782  df-ral 2901  df-rex 2902  df-rab 2905  df-v 3175  df-sbc 3403  df-dif 3543  df-un 3545  df-in 3547  df-ss 3554  df-pss 3556  df-nul 3875  df-if 4037  df-pw 4110  df-sn 4126  df-pr 4128  df-tp 4130  df-op 4132  df-uni 4373  df-br 4584  df-opab 4644  df-tr 4681  df-eprel 4949  df-po 4959  df-so 4960  df-fr 4997  df-we 4999  df-ord 5643  df-on 5644  df-lim 5645  df-suc 5646  df-om 6958  df-1o 7447

This theorem is referenced by:  bnj600  30243