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Theorem indpi 10860
Description: Principle of Finite Induction on positive integers. (Contributed by NM, 23-Mar-1996.) (New usage is discouraged.)
Hypotheses
Ref Expression
indpi.1 (𝑥 = 1o → (𝜑𝜓))
indpi.2 (𝑥 = 𝑦 → (𝜑𝜒))
indpi.3 (𝑥 = (𝑦 +N 1o) → (𝜑𝜃))
indpi.4 (𝑥 = 𝐴 → (𝜑𝜏))
indpi.5 𝜓
indpi.6 (𝑦N → (𝜒𝜃))
Assertion
Ref Expression
indpi (𝐴N𝜏)
Distinct variable groups:   𝑥,𝑦   𝑥,𝐴   𝜓,𝑥   𝜒,𝑥   𝜃,𝑥   𝜏,𝑥   𝜑,𝑦
Allowed substitution hints:   𝜑(𝑥)   𝜓(𝑦)   𝜒(𝑦)   𝜃(𝑦)   𝜏(𝑦)   𝐴(𝑦)

Proof of Theorem indpi
StepHypRef Expression
1 1oex 8444 . . . . . 6 1o ∈ V
21eqvinc 3615 . . . . 5 (1o = 𝐴 ↔ ∃𝑥(𝑥 = 1o𝑥 = 𝐴))
3 indpi.4 . . . . 5 (𝑥 = 𝐴 → (𝜑𝜏))
4 indpi.5 . . . . . 6 𝜓
5 indpi.1 . . . . . 6 (𝑥 = 1o → (𝜑𝜓))
64, 5mpbiri 258 . . . . 5 (𝑥 = 1o𝜑)
72, 3, 6gencl 3489 . . . 4 (1o = 𝐴𝜏)
87eqcoms 2737 . . 3 (𝐴 = 1o𝜏)
98a1i 11 . 2 (𝐴N → (𝐴 = 1o𝜏))
10 pinn 10831 . . . . 5 (𝐴N𝐴 ∈ ω)
11 elni2 10830 . . . . . 6 (𝐴N ↔ (𝐴 ∈ ω ∧ ∅ ∈ 𝐴))
12 nnord 7850 . . . . . . . . 9 (𝐴 ∈ ω → Ord 𝐴)
13 ordsucss 7793 . . . . . . . . 9 (Ord 𝐴 → (∅ ∈ 𝐴 → suc ∅ ⊆ 𝐴))
1412, 13syl 17 . . . . . . . 8 (𝐴 ∈ ω → (∅ ∈ 𝐴 → suc ∅ ⊆ 𝐴))
15 df-1o 8434 . . . . . . . . 9 1o = suc ∅
1615sseq1i 3975 . . . . . . . 8 (1o𝐴 ↔ suc ∅ ⊆ 𝐴)
1714, 16imbitrrdi 252 . . . . . . 7 (𝐴 ∈ ω → (∅ ∈ 𝐴 → 1o𝐴))
1817imp 406 . . . . . 6 ((𝐴 ∈ ω ∧ ∅ ∈ 𝐴) → 1o𝐴)
1911, 18sylbi 217 . . . . 5 (𝐴N → 1o𝐴)
20 1onn 8604 . . . . . 6 1o ∈ ω
21 eleq1 2816 . . . . . . . . 9 (𝑥 = 1o → (𝑥N ↔ 1oN))
22 breq2 5111 . . . . . . . . 9 (𝑥 = 1o → (1o <N 𝑥 ↔ 1o <N 1o))
2321, 22anbi12d 632 . . . . . . . 8 (𝑥 = 1o → ((𝑥N ∧ 1o <N 𝑥) ↔ (1oN ∧ 1o <N 1o)))
2423, 5imbi12d 344 . . . . . . 7 (𝑥 = 1o → (((𝑥N ∧ 1o <N 𝑥) → 𝜑) ↔ ((1oN ∧ 1o <N 1o) → 𝜓)))
25 eleq1 2816 . . . . . . . . 9 (𝑥 = 𝑦 → (𝑥N𝑦N))
26 breq2 5111 . . . . . . . . 9 (𝑥 = 𝑦 → (1o <N 𝑥 ↔ 1o <N 𝑦))
2725, 26anbi12d 632 . . . . . . . 8 (𝑥 = 𝑦 → ((𝑥N ∧ 1o <N 𝑥) ↔ (𝑦N ∧ 1o <N 𝑦)))
28 indpi.2 . . . . . . . 8 (𝑥 = 𝑦 → (𝜑𝜒))
2927, 28imbi12d 344 . . . . . . 7 (𝑥 = 𝑦 → (((𝑥N ∧ 1o <N 𝑥) → 𝜑) ↔ ((𝑦N ∧ 1o <N 𝑦) → 𝜒)))
30 pinn 10831 . . . . . . . . . . . . . . 15 (𝑥N𝑥 ∈ ω)
31 eleq1 2816 . . . . . . . . . . . . . . . 16 (𝑥 = suc 𝑦 → (𝑥 ∈ ω ↔ suc 𝑦 ∈ ω))
32 peano2b 7859 . . . . . . . . . . . . . . . 16 (𝑦 ∈ ω ↔ suc 𝑦 ∈ ω)
3331, 32bitr4di 289 . . . . . . . . . . . . . . 15 (𝑥 = suc 𝑦 → (𝑥 ∈ ω ↔ 𝑦 ∈ ω))
3430, 33imbitrid 244 . . . . . . . . . . . . . 14 (𝑥 = suc 𝑦 → (𝑥N𝑦 ∈ ω))
3534adantrd 491 . . . . . . . . . . . . 13 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → 𝑦 ∈ ω))
36 1pi 10836 . . . . . . . . . . . . . . . 16 1oN
37 ltpiord 10840 . . . . . . . . . . . . . . . 16 ((1oN𝑥N) → (1o <N 𝑥 ↔ 1o𝑥))
3836, 37mpan 690 . . . . . . . . . . . . . . 15 (𝑥N → (1o <N 𝑥 ↔ 1o𝑥))
3938biimpa 476 . . . . . . . . . . . . . 14 ((𝑥N ∧ 1o <N 𝑥) → 1o𝑥)
40 eleq2 2817 . . . . . . . . . . . . . . 15 (𝑥 = suc 𝑦 → (1o𝑥 ↔ 1o ∈ suc 𝑦))
41 elsuci 6401 . . . . . . . . . . . . . . . 16 (1o ∈ suc 𝑦 → (1o𝑦 ∨ 1o = 𝑦))
42 ne0i 4304 . . . . . . . . . . . . . . . . 17 (1o𝑦𝑦 ≠ ∅)
43 0lt1o 8468 . . . . . . . . . . . . . . . . . . 19 ∅ ∈ 1o
44 eleq2 2817 . . . . . . . . . . . . . . . . . . 19 (1o = 𝑦 → (∅ ∈ 1o ↔ ∅ ∈ 𝑦))
4543, 44mpbii 233 . . . . . . . . . . . . . . . . . 18 (1o = 𝑦 → ∅ ∈ 𝑦)
4645ne0d 4305 . . . . . . . . . . . . . . . . 17 (1o = 𝑦𝑦 ≠ ∅)
4742, 46jaoi 857 . . . . . . . . . . . . . . . 16 ((1o𝑦 ∨ 1o = 𝑦) → 𝑦 ≠ ∅)
4841, 47syl 17 . . . . . . . . . . . . . . 15 (1o ∈ suc 𝑦𝑦 ≠ ∅)
4940, 48biimtrdi 253 . . . . . . . . . . . . . 14 (𝑥 = suc 𝑦 → (1o𝑥𝑦 ≠ ∅))
5039, 49syl5 34 . . . . . . . . . . . . 13 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → 𝑦 ≠ ∅))
5135, 50jcad 512 . . . . . . . . . . . 12 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → (𝑦 ∈ ω ∧ 𝑦 ≠ ∅)))
52 elni 10829 . . . . . . . . . . . 12 (𝑦N ↔ (𝑦 ∈ ω ∧ 𝑦 ≠ ∅))
5351, 52imbitrrdi 252 . . . . . . . . . . 11 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → 𝑦N))
54 simpr 484 . . . . . . . . . . . 12 ((𝑥N ∧ 1o <N 𝑥) → 1o <N 𝑥)
55 breq2 5111 . . . . . . . . . . . 12 (𝑥 = suc 𝑦 → (1o <N 𝑥 ↔ 1o <N suc 𝑦))
5654, 55imbitrid 244 . . . . . . . . . . 11 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → 1o <N suc 𝑦))
5753, 56jcad 512 . . . . . . . . . 10 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → (𝑦N ∧ 1o <N suc 𝑦)))
58 addclpi 10845 . . . . . . . . . . . . . . 15 ((𝑦N ∧ 1oN) → (𝑦 +N 1o) ∈ N)
5936, 58mpan2 691 . . . . . . . . . . . . . 14 (𝑦N → (𝑦 +N 1o) ∈ N)
60 addpiord 10837 . . . . . . . . . . . . . . . . . . 19 ((𝑦N ∧ 1oN) → (𝑦 +N 1o) = (𝑦 +o 1o))
6136, 60mpan2 691 . . . . . . . . . . . . . . . . . 18 (𝑦N → (𝑦 +N 1o) = (𝑦 +o 1o))
62 pion 10832 . . . . . . . . . . . . . . . . . . 19 (𝑦N𝑦 ∈ On)
63 oa1suc 8495 . . . . . . . . . . . . . . . . . . 19 (𝑦 ∈ On → (𝑦 +o 1o) = suc 𝑦)
6462, 63syl 17 . . . . . . . . . . . . . . . . . 18 (𝑦N → (𝑦 +o 1o) = suc 𝑦)
6561, 64eqtrd 2764 . . . . . . . . . . . . . . . . 17 (𝑦N → (𝑦 +N 1o) = suc 𝑦)
6665eqeq2d 2740 . . . . . . . . . . . . . . . 16 (𝑦N → (𝑥 = (𝑦 +N 1o) ↔ 𝑥 = suc 𝑦))
6766biimparc 479 . . . . . . . . . . . . . . 15 ((𝑥 = suc 𝑦𝑦N) → 𝑥 = (𝑦 +N 1o))
6867eleq1d 2813 . . . . . . . . . . . . . 14 ((𝑥 = suc 𝑦𝑦N) → (𝑥N ↔ (𝑦 +N 1o) ∈ N))
6959, 68imbitrrid 246 . . . . . . . . . . . . 13 ((𝑥 = suc 𝑦𝑦N) → (𝑦N𝑥N))
7069ex 412 . . . . . . . . . . . 12 (𝑥 = suc 𝑦 → (𝑦N → (𝑦N𝑥N)))
7170pm2.43d 53 . . . . . . . . . . 11 (𝑥 = suc 𝑦 → (𝑦N𝑥N))
7255biimprd 248 . . . . . . . . . . 11 (𝑥 = suc 𝑦 → (1o <N suc 𝑦 → 1o <N 𝑥))
7371, 72anim12d 609 . . . . . . . . . 10 (𝑥 = suc 𝑦 → ((𝑦N ∧ 1o <N suc 𝑦) → (𝑥N ∧ 1o <N 𝑥)))
7457, 73impbid 212 . . . . . . . . 9 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) ↔ (𝑦N ∧ 1o <N suc 𝑦)))
7574imbi1d 341 . . . . . . . 8 (𝑥 = suc 𝑦 → (((𝑥N ∧ 1o <N 𝑥) → 𝜑) ↔ ((𝑦N ∧ 1o <N suc 𝑦) → 𝜑)))
76 indpi.3 . . . . . . . . . . . 12 (𝑥 = (𝑦 +N 1o) → (𝜑𝜃))
7766, 76biimtrrdi 254 . . . . . . . . . . 11 (𝑦N → (𝑥 = suc 𝑦 → (𝜑𝜃)))
7877adantr 480 . . . . . . . . . 10 ((𝑦N ∧ 1o <N suc 𝑦) → (𝑥 = suc 𝑦 → (𝜑𝜃)))
7978com12 32 . . . . . . . . 9 (𝑥 = suc 𝑦 → ((𝑦N ∧ 1o <N suc 𝑦) → (𝜑𝜃)))
8079pm5.74d 273 . . . . . . . 8 (𝑥 = suc 𝑦 → (((𝑦N ∧ 1o <N suc 𝑦) → 𝜑) ↔ ((𝑦N ∧ 1o <N suc 𝑦) → 𝜃)))
8175, 80bitrd 279 . . . . . . 7 (𝑥 = suc 𝑦 → (((𝑥N ∧ 1o <N 𝑥) → 𝜑) ↔ ((𝑦N ∧ 1o <N suc 𝑦) → 𝜃)))
82 eleq1 2816 . . . . . . . . 9 (𝑥 = 𝐴 → (𝑥N𝐴N))
83 breq2 5111 . . . . . . . . 9 (𝑥 = 𝐴 → (1o <N 𝑥 ↔ 1o <N 𝐴))
8482, 83anbi12d 632 . . . . . . . 8 (𝑥 = 𝐴 → ((𝑥N ∧ 1o <N 𝑥) ↔ (𝐴N ∧ 1o <N 𝐴)))
8584, 3imbi12d 344 . . . . . . 7 (𝑥 = 𝐴 → (((𝑥N ∧ 1o <N 𝑥) → 𝜑) ↔ ((𝐴N ∧ 1o <N 𝐴) → 𝜏)))
8642a1i 12 . . . . . . 7 (1o ∈ ω → ((1oN ∧ 1o <N 1o) → 𝜓))
87 ltpiord 10840 . . . . . . . . . . . . . . 15 ((1oN𝑦N) → (1o <N 𝑦 ↔ 1o𝑦))
8836, 87mpan 690 . . . . . . . . . . . . . 14 (𝑦N → (1o <N 𝑦 ↔ 1o𝑦))
8988pm5.32i 574 . . . . . . . . . . . . 13 ((𝑦N ∧ 1o <N 𝑦) ↔ (𝑦N ∧ 1o𝑦))
9089simplbi2 500 . . . . . . . . . . . 12 (𝑦N → (1o𝑦 → (𝑦N ∧ 1o <N 𝑦)))
9190imim1d 82 . . . . . . . . . . 11 (𝑦N → (((𝑦N ∧ 1o <N 𝑦) → 𝜒) → (1o𝑦𝜒)))
92 ltrelpi 10842 . . . . . . . . . . . . . . 15 <N ⊆ (N × N)
9392brel 5703 . . . . . . . . . . . . . 14 (1o <N suc 𝑦 → (1oN ∧ suc 𝑦N))
94 ltpiord 10840 . . . . . . . . . . . . . 14 ((1oN ∧ suc 𝑦N) → (1o <N suc 𝑦 ↔ 1o ∈ suc 𝑦))
9593, 94syl 17 . . . . . . . . . . . . 13 (1o <N suc 𝑦 → (1o <N suc 𝑦 ↔ 1o ∈ suc 𝑦))
9695ibi 267 . . . . . . . . . . . 12 (1o <N suc 𝑦 → 1o ∈ suc 𝑦)
971eqvinc 3615 . . . . . . . . . . . . . . 15 (1o = 𝑦 ↔ ∃𝑥(𝑥 = 1o𝑥 = 𝑦))
9897, 28, 6gencl 3489 . . . . . . . . . . . . . 14 (1o = 𝑦𝜒)
99 jao 962 . . . . . . . . . . . . . 14 ((1o𝑦𝜒) → ((1o = 𝑦𝜒) → ((1o𝑦 ∨ 1o = 𝑦) → 𝜒)))
10098, 99mpi 20 . . . . . . . . . . . . 13 ((1o𝑦𝜒) → ((1o𝑦 ∨ 1o = 𝑦) → 𝜒))
10141, 100syl5 34 . . . . . . . . . . . 12 ((1o𝑦𝜒) → (1o ∈ suc 𝑦𝜒))
10296, 101syl5 34 . . . . . . . . . . 11 ((1o𝑦𝜒) → (1o <N suc 𝑦𝜒))
10391, 102syl6com 37 . . . . . . . . . 10 (((𝑦N ∧ 1o <N 𝑦) → 𝜒) → (𝑦N → (1o <N suc 𝑦𝜒)))
104103impd 410 . . . . . . . . 9 (((𝑦N ∧ 1o <N 𝑦) → 𝜒) → ((𝑦N ∧ 1o <N suc 𝑦) → 𝜒))
10515sseq1i 3975 . . . . . . . . . . 11 (1o𝑦 ↔ suc ∅ ⊆ 𝑦)
106 0ex 5262 . . . . . . . . . . . 12 ∅ ∈ V
107 sucssel 6429 . . . . . . . . . . . 12 (∅ ∈ V → (suc ∅ ⊆ 𝑦 → ∅ ∈ 𝑦))
108106, 107ax-mp 5 . . . . . . . . . . 11 (suc ∅ ⊆ 𝑦 → ∅ ∈ 𝑦)
109105, 108sylbi 217 . . . . . . . . . 10 (1o𝑦 → ∅ ∈ 𝑦)
110 elni2 10830 . . . . . . . . . . 11 (𝑦N ↔ (𝑦 ∈ ω ∧ ∅ ∈ 𝑦))
111 indpi.6 . . . . . . . . . . 11 (𝑦N → (𝜒𝜃))
112110, 111sylbir 235 . . . . . . . . . 10 ((𝑦 ∈ ω ∧ ∅ ∈ 𝑦) → (𝜒𝜃))
113109, 112sylan2 593 . . . . . . . . 9 ((𝑦 ∈ ω ∧ 1o𝑦) → (𝜒𝜃))
114104, 113syl9r 78 . . . . . . . 8 ((𝑦 ∈ ω ∧ 1o𝑦) → (((𝑦N ∧ 1o <N 𝑦) → 𝜒) → ((𝑦N ∧ 1o <N suc 𝑦) → 𝜃)))
115114adantlr 715 . . . . . . 7 (((𝑦 ∈ ω ∧ 1o ∈ ω) ∧ 1o𝑦) → (((𝑦N ∧ 1o <N 𝑦) → 𝜒) → ((𝑦N ∧ 1o <N suc 𝑦) → 𝜃)))
11624, 29, 81, 85, 86, 115findsg 7873 . . . . . 6 (((𝐴 ∈ ω ∧ 1o ∈ ω) ∧ 1o𝐴) → ((𝐴N ∧ 1o <N 𝐴) → 𝜏))
11720, 116mpanl2 701 . . . . 5 ((𝐴 ∈ ω ∧ 1o𝐴) → ((𝐴N ∧ 1o <N 𝐴) → 𝜏))
11810, 19, 117syl2anc 584 . . . 4 (𝐴N → ((𝐴N ∧ 1o <N 𝐴) → 𝜏))
119118expd 415 . . 3 (𝐴N → (𝐴N → (1o <N 𝐴𝜏)))
120119pm2.43i 52 . 2 (𝐴N → (1o <N 𝐴𝜏))
121 nlt1pi 10859 . . . 4 ¬ 𝐴 <N 1o
122 ltsopi 10841 . . . . . 6 <N Or N
123 sotric 5576 . . . . . 6 (( <N Or N ∧ (𝐴N ∧ 1oN)) → (𝐴 <N 1o ↔ ¬ (𝐴 = 1o ∨ 1o <N 𝐴)))
124122, 123mpan 690 . . . . 5 ((𝐴N ∧ 1oN) → (𝐴 <N 1o ↔ ¬ (𝐴 = 1o ∨ 1o <N 𝐴)))
12536, 124mpan2 691 . . . 4 (𝐴N → (𝐴 <N 1o ↔ ¬ (𝐴 = 1o ∨ 1o <N 𝐴)))
126121, 125mtbii 326 . . 3 (𝐴N → ¬ ¬ (𝐴 = 1o ∨ 1o <N 𝐴))
127126notnotrd 133 . 2 (𝐴N → (𝐴 = 1o ∨ 1o <N 𝐴))
1289, 120, 127mpjaod 860 1 (𝐴N𝜏)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 206  wa 395  wo 847   = wceq 1540  wcel 2109  wne 2925  Vcvv 3447  wss 3914  c0 4296   class class class wbr 5107   Or wor 5545  Ord word 6331  Oncon0 6332  suc csuc 6334  (class class class)co 7387  ωcom 7842  1oc1o 8427   +o coa 8431  Ncnpi 10797   +N cpli 10798   <N clti 10800
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-10 2142  ax-11 2158  ax-12 2178  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-nf 1784  df-sb 2066  df-mo 2533  df-eu 2562  df-clab 2708  df-cleq 2721  df-clel 2803  df-nfc 2878  df-ne 2926  df-ral 3045  df-rex 3054  df-reu 3355  df-rab 3406  df-v 3449  df-sbc 3754  df-csb 3863  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-iun 4957  df-br 5108  df-opab 5170  df-mpt 5189  df-tr 5215  df-id 5533  df-eprel 5538  df-po 5546  df-so 5547  df-fr 5591  df-we 5593  df-xp 5644  df-rel 5645  df-cnv 5646  df-co 5647  df-dm 5648  df-rn 5649  df-res 5650  df-ima 5651  df-pred 6274  df-ord 6335  df-on 6336  df-lim 6337  df-suc 6338  df-iota 6464  df-fun 6513  df-fn 6514  df-f 6515  df-f1 6516  df-fo 6517  df-f1o 6518  df-fv 6519  df-ov 7390  df-oprab 7391  df-mpo 7392  df-om 7843  df-2nd 7969  df-frecs 8260  df-wrecs 8291  df-recs 8340  df-rdg 8378  df-1o 8434  df-oadd 8438  df-ni 10825  df-pli 10826  df-lti 10828
This theorem is referenced by:  prlem934  10986
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