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Theorem indpi 10828
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 8412 . . . . . 6 1o ∈ V
21eqvinc 3594 . . . . 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 259 . . . . 5 (𝑥 = 1o𝜑)
72, 3, 6gencl 3474 . . . 4 (1o = 𝐴𝜏)
87eqcoms 2748 . . 3 (𝐴 = 1o𝜏)
98a1i 11 . 2 (𝐴N → (𝐴 = 1o𝜏))
10 pinn 10799 . . . . 5 (𝐴N𝐴 ∈ ω)
11 elni2 10798 . . . . . 6 (𝐴N ↔ (𝐴 ∈ ω ∧ ∅ ∈ 𝐴))
12 nnord 7821 . . . . . . . . 9 (𝐴 ∈ ω → Ord 𝐴)
13 ordsucss 7765 . . . . . . . . 9 (Ord 𝐴 → (∅ ∈ 𝐴 → suc ∅ ⊆ 𝐴))
1412, 13syl 17 . . . . . . . 8 (𝐴 ∈ ω → (∅ ∈ 𝐴 → suc ∅ ⊆ 𝐴))
15 df-1o 8402 . . . . . . . . 9 1o = suc ∅
1615sseq1i 3950 . . . . . . . 8 (1o𝐴 ↔ suc ∅ ⊆ 𝐴)
1714, 16imbitrrdi 253 . . . . . . 7 (𝐴 ∈ ω → (∅ ∈ 𝐴 → 1o𝐴))
1817imp 407 . . . . . 6 ((𝐴 ∈ ω ∧ ∅ ∈ 𝐴) → 1o𝐴)
1911, 18sylbi 218 . . . . 5 (𝐴N → 1o𝐴)
20 1onn 8573 . . . . . 6 1o ∈ ω
21 eleq1 2828 . . . . . . . . 9 (𝑥 = 1o → (𝑥N ↔ 1oN))
22 breq2 5083 . . . . . . . . 9 (𝑥 = 1o → (1o <N 𝑥 ↔ 1o <N 1o))
2321, 22anbi12d 638 . . . . . . . 8 (𝑥 = 1o → ((𝑥N ∧ 1o <N 𝑥) ↔ (1oN ∧ 1o <N 1o)))
2423, 5imbi12d 345 . . . . . . 7 (𝑥 = 1o → (((𝑥N ∧ 1o <N 𝑥) → 𝜑) ↔ ((1oN ∧ 1o <N 1o) → 𝜓)))
25 eleq1 2828 . . . . . . . . 9 (𝑥 = 𝑦 → (𝑥N𝑦N))
26 breq2 5083 . . . . . . . . 9 (𝑥 = 𝑦 → (1o <N 𝑥 ↔ 1o <N 𝑦))
2725, 26anbi12d 638 . . . . . . . 8 (𝑥 = 𝑦 → ((𝑥N ∧ 1o <N 𝑥) ↔ (𝑦N ∧ 1o <N 𝑦)))
28 indpi.2 . . . . . . . 8 (𝑥 = 𝑦 → (𝜑𝜒))
2927, 28imbi12d 345 . . . . . . 7 (𝑥 = 𝑦 → (((𝑥N ∧ 1o <N 𝑥) → 𝜑) ↔ ((𝑦N ∧ 1o <N 𝑦) → 𝜒)))
30 pinn 10799 . . . . . . . . . . . . . . 15 (𝑥N𝑥 ∈ ω)
31 eleq1 2828 . . . . . . . . . . . . . . . 16 (𝑥 = suc 𝑦 → (𝑥 ∈ ω ↔ suc 𝑦 ∈ ω))
32 peano2b 7830 . . . . . . . . . . . . . . . 16 (𝑦 ∈ ω ↔ suc 𝑦 ∈ ω)
3331, 32bitr4di 290 . . . . . . . . . . . . . . 15 (𝑥 = suc 𝑦 → (𝑥 ∈ ω ↔ 𝑦 ∈ ω))
3430, 33imbitrid 245 . . . . . . . . . . . . . 14 (𝑥 = suc 𝑦 → (𝑥N𝑦 ∈ ω))
3534adantrd 492 . . . . . . . . . . . . 13 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → 𝑦 ∈ ω))
36 1pi 10804 . . . . . . . . . . . . . . . 16 1oN
37 ltpiord 10808 . . . . . . . . . . . . . . . 16 ((1oN𝑥N) → (1o <N 𝑥 ↔ 1o𝑥))
3836, 37mpan 696 . . . . . . . . . . . . . . 15 (𝑥N → (1o <N 𝑥 ↔ 1o𝑥))
3938biimpa 477 . . . . . . . . . . . . . 14 ((𝑥N ∧ 1o <N 𝑥) → 1o𝑥)
40 eleq2 2829 . . . . . . . . . . . . . . 15 (𝑥 = suc 𝑦 → (1o𝑥 ↔ 1o ∈ suc 𝑦))
41 elsuci 6386 . . . . . . . . . . . . . . . 16 (1o ∈ suc 𝑦 → (1o𝑦 ∨ 1o = 𝑦))
42 ne0i 4276 . . . . . . . . . . . . . . . . 17 (1o𝑦𝑦 ≠ ∅)
43 0lt1o 8436 . . . . . . . . . . . . . . . . . . 19 ∅ ∈ 1o
44 eleq2 2829 . . . . . . . . . . . . . . . . . . 19 (1o = 𝑦 → (∅ ∈ 1o ↔ ∅ ∈ 𝑦))
4543, 44mpbii 234 . . . . . . . . . . . . . . . . . 18 (1o = 𝑦 → ∅ ∈ 𝑦)
4645ne0d 4277 . . . . . . . . . . . . . . . . 17 (1o = 𝑦𝑦 ≠ ∅)
4742, 46jaoi 863 . . . . . . . . . . . . . . . 16 ((1o𝑦 ∨ 1o = 𝑦) → 𝑦 ≠ ∅)
4841, 47syl 17 . . . . . . . . . . . . . . 15 (1o ∈ suc 𝑦𝑦 ≠ ∅)
4940, 48biimtrdi 254 . . . . . . . . . . . . . 14 (𝑥 = suc 𝑦 → (1o𝑥𝑦 ≠ ∅))
5039, 49syl5 34 . . . . . . . . . . . . 13 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → 𝑦 ≠ ∅))
5135, 50jcad 517 . . . . . . . . . . . 12 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → (𝑦 ∈ ω ∧ 𝑦 ≠ ∅)))
52 elni 10797 . . . . . . . . . . . 12 (𝑦N ↔ (𝑦 ∈ ω ∧ 𝑦 ≠ ∅))
5351, 52imbitrrdi 253 . . . . . . . . . . 11 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → 𝑦N))
54 simpr 485 . . . . . . . . . . . 12 ((𝑥N ∧ 1o <N 𝑥) → 1o <N 𝑥)
55 breq2 5083 . . . . . . . . . . . 12 (𝑥 = suc 𝑦 → (1o <N 𝑥 ↔ 1o <N suc 𝑦))
5654, 55imbitrid 245 . . . . . . . . . . 11 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → 1o <N suc 𝑦))
5753, 56jcad 517 . . . . . . . . . 10 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) → (𝑦N ∧ 1o <N suc 𝑦)))
58 addclpi 10813 . . . . . . . . . . . . . . 15 ((𝑦N ∧ 1oN) → (𝑦 +N 1o) ∈ N)
5936, 58mpan2 697 . . . . . . . . . . . . . 14 (𝑦N → (𝑦 +N 1o) ∈ N)
60 addpiord 10805 . . . . . . . . . . . . . . . . . . 19 ((𝑦N ∧ 1oN) → (𝑦 +N 1o) = (𝑦 +o 1o))
6136, 60mpan2 697 . . . . . . . . . . . . . . . . . 18 (𝑦N → (𝑦 +N 1o) = (𝑦 +o 1o))
62 pion 10800 . . . . . . . . . . . . . . . . . . 19 (𝑦N𝑦 ∈ On)
63 oa1suc 8463 . . . . . . . . . . . . . . . . . . 19 (𝑦 ∈ On → (𝑦 +o 1o) = suc 𝑦)
6462, 63syl 17 . . . . . . . . . . . . . . . . . 18 (𝑦N → (𝑦 +o 1o) = suc 𝑦)
6561, 64eqtrd 2775 . . . . . . . . . . . . . . . . 17 (𝑦N → (𝑦 +N 1o) = suc 𝑦)
6665eqeq2d 2751 . . . . . . . . . . . . . . . 16 (𝑦N → (𝑥 = (𝑦 +N 1o) ↔ 𝑥 = suc 𝑦))
6766biimparc 480 . . . . . . . . . . . . . . 15 ((𝑥 = suc 𝑦𝑦N) → 𝑥 = (𝑦 +N 1o))
6867eleq1d 2825 . . . . . . . . . . . . . 14 ((𝑥 = suc 𝑦𝑦N) → (𝑥N ↔ (𝑦 +N 1o) ∈ N))
6959, 68imbitrrid 247 . . . . . . . . . . . . 13 ((𝑥 = suc 𝑦𝑦N) → (𝑦N𝑥N))
7069ex 413 . . . . . . . . . . . 12 (𝑥 = suc 𝑦 → (𝑦N → (𝑦N𝑥N)))
7170pm2.43d 53 . . . . . . . . . . 11 (𝑥 = suc 𝑦 → (𝑦N𝑥N))
7255biimprd 249 . . . . . . . . . . 11 (𝑥 = suc 𝑦 → (1o <N suc 𝑦 → 1o <N 𝑥))
7371, 72anim12d 615 . . . . . . . . . 10 (𝑥 = suc 𝑦 → ((𝑦N ∧ 1o <N suc 𝑦) → (𝑥N ∧ 1o <N 𝑥)))
7457, 73impbid 213 . . . . . . . . 9 (𝑥 = suc 𝑦 → ((𝑥N ∧ 1o <N 𝑥) ↔ (𝑦N ∧ 1o <N suc 𝑦)))
7574imbi1d 342 . . . . . . . 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 255 . . . . . . . . . . 11 (𝑦N → (𝑥 = suc 𝑦 → (𝜑𝜃)))
7877adantr 481 . . . . . . . . . 10 ((𝑦N ∧ 1o <N suc 𝑦) → (𝑥 = suc 𝑦 → (𝜑𝜃)))
7978com12 32 . . . . . . . . 9 (𝑥 = suc 𝑦 → ((𝑦N ∧ 1o <N suc 𝑦) → (𝜑𝜃)))
8079pm5.74d 274 . . . . . . . 8 (𝑥 = suc 𝑦 → (((𝑦N ∧ 1o <N suc 𝑦) → 𝜑) ↔ ((𝑦N ∧ 1o <N suc 𝑦) → 𝜃)))
8175, 80bitrd 280 . . . . . . 7 (𝑥 = suc 𝑦 → (((𝑥N ∧ 1o <N 𝑥) → 𝜑) ↔ ((𝑦N ∧ 1o <N suc 𝑦) → 𝜃)))
82 eleq1 2828 . . . . . . . . 9 (𝑥 = 𝐴 → (𝑥N𝐴N))
83 breq2 5083 . . . . . . . . 9 (𝑥 = 𝐴 → (1o <N 𝑥 ↔ 1o <N 𝐴))
8482, 83anbi12d 638 . . . . . . . 8 (𝑥 = 𝐴 → ((𝑥N ∧ 1o <N 𝑥) ↔ (𝐴N ∧ 1o <N 𝐴)))
8584, 3imbi12d 345 . . . . . . 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 10808 . . . . . . . . . . . . . . 15 ((1oN𝑦N) → (1o <N 𝑦 ↔ 1o𝑦))
8836, 87mpan 696 . . . . . . . . . . . . . 14 (𝑦N → (1o <N 𝑦 ↔ 1o𝑦))
8988pm5.32i 579 . . . . . . . . . . . . 13 ((𝑦N ∧ 1o <N 𝑦) ↔ (𝑦N ∧ 1o𝑦))
9089simplbi2 501 . . . . . . . . . . . 12 (𝑦N → (1o𝑦 → (𝑦N ∧ 1o <N 𝑦)))
9190imim1d 82 . . . . . . . . . . 11 (𝑦N → (((𝑦N ∧ 1o <N 𝑦) → 𝜒) → (1o𝑦𝜒)))
92 ltrelpi 10810 . . . . . . . . . . . . . . 15 <N ⊆ (N × N)
9392brel 5690 . . . . . . . . . . . . . 14 (1o <N suc 𝑦 → (1oN ∧ suc 𝑦N))
94 ltpiord 10808 . . . . . . . . . . . . . 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 268 . . . . . . . . . . . 12 (1o <N suc 𝑦 → 1o ∈ suc 𝑦)
971eqvinc 3594 . . . . . . . . . . . . . . 15 (1o = 𝑦 ↔ ∃𝑥(𝑥 = 1o𝑥 = 𝑦))
9897, 28, 6gencl 3474 . . . . . . . . . . . . . 14 (1o = 𝑦𝜒)
99 jao 968 . . . . . . . . . . . . . 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 411 . . . . . . . . 9 (((𝑦N ∧ 1o <N 𝑦) → 𝜒) → ((𝑦N ∧ 1o <N suc 𝑦) → 𝜒))
10515sseq1i 3950 . . . . . . . . . . 11 (1o𝑦 ↔ suc ∅ ⊆ 𝑦)
106 0ex 5236 . . . . . . . . . . . 12 ∅ ∈ V
107 sucssel 6414 . . . . . . . . . . . 12 (∅ ∈ V → (suc ∅ ⊆ 𝑦 → ∅ ∈ 𝑦))
108106, 107ax-mp 5 . . . . . . . . . . 11 (suc ∅ ⊆ 𝑦 → ∅ ∈ 𝑦)
109105, 108sylbi 218 . . . . . . . . . 10 (1o𝑦 → ∅ ∈ 𝑦)
110 elni2 10798 . . . . . . . . . . 11 (𝑦N ↔ (𝑦 ∈ ω ∧ ∅ ∈ 𝑦))
111 indpi.6 . . . . . . . . . . 11 (𝑦N → (𝜒𝜃))
112110, 111sylbir 236 . . . . . . . . . 10 ((𝑦 ∈ ω ∧ ∅ ∈ 𝑦) → (𝜒𝜃))
113109, 112sylan2 599 . . . . . . . . 9 ((𝑦 ∈ ω ∧ 1o𝑦) → (𝜒𝜃))
114104, 113syl9r 78 . . . . . . . 8 ((𝑦 ∈ ω ∧ 1o𝑦) → (((𝑦N ∧ 1o <N 𝑦) → 𝜒) → ((𝑦N ∧ 1o <N suc 𝑦) → 𝜃)))
115114adantlr 721 . . . . . . 7 (((𝑦 ∈ ω ∧ 1o ∈ ω) ∧ 1o𝑦) → (((𝑦N ∧ 1o <N 𝑦) → 𝜒) → ((𝑦N ∧ 1o <N suc 𝑦) → 𝜃)))
11624, 29, 81, 85, 86, 115findsg 7844 . . . . . 6 (((𝐴 ∈ ω ∧ 1o ∈ ω) ∧ 1o𝐴) → ((𝐴N ∧ 1o <N 𝐴) → 𝜏))
11720, 116mpanl2 707 . . . . 5 ((𝐴 ∈ ω ∧ 1o𝐴) → ((𝐴N ∧ 1o <N 𝐴) → 𝜏))
11810, 19, 117syl2anc 590 . . . 4 (𝐴N → ((𝐴N ∧ 1o <N 𝐴) → 𝜏))
119118expd 416 . . 3 (𝐴N → (𝐴N → (1o <N 𝐴𝜏)))
120119pm2.43i 52 . 2 (𝐴N → (1o <N 𝐴𝜏))
121 nlt1pi 10827 . . . 4 ¬ 𝐴 <N 1o
122 ltsopi 10809 . . . . . 6 <N Or N
123 sotric 5563 . . . . . 6 (( <N Or N ∧ (𝐴N ∧ 1oN)) → (𝐴 <N 1o ↔ ¬ (𝐴 = 1o ∨ 1o <N 𝐴)))
124122, 123mpan 696 . . . . 5 ((𝐴N ∧ 1oN) → (𝐴 <N 1o ↔ ¬ (𝐴 = 1o ∨ 1o <N 𝐴)))
12536, 124mpan2 697 . . . 4 (𝐴N → (𝐴 <N 1o ↔ ¬ (𝐴 = 1o ∨ 1o <N 𝐴)))
126121, 125mtbii 327 . . 3 (𝐴N → ¬ ¬ (𝐴 = 1o ∨ 1o <N 𝐴))
127126notnotrd 133 . 2 (𝐴N → (𝐴 = 1o ∨ 1o <N 𝐴))
1289, 120, 127mpjaod 866 1 (𝐴N𝜏)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 207  wa 396  wo 853   = wceq 1547  wcel 2119  wne 2935  Vcvv 3432  wss 3890  c0 4268   class class class wbr 5079   Or wor 5532  Ord word 6316  Oncon0 6317  suc csuc 6319  (class class class)co 7363  ωcom 7813  1oc1o 8395   +o coa 8399  Ncnpi 10765   +N cpli 10766   <N clti 10768
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1917  ax-6 1974  ax-7 2015  ax-8 2121  ax-9 2129  ax-10 2152  ax-11 2168  ax-12 2189  ax-ext 2712  ax-sep 5225  ax-nul 5235  ax-pr 5369  ax-un 7685
This theorem depends on definitions:  df-bi 208  df-an 397  df-or 854  df-3or 1093  df-3an 1094  df-tru 1550  df-fal 1560  df-ex 1787  df-nf 1791  df-sb 2074  df-mo 2543  df-eu 2573  df-clab 2719  df-cleq 2732  df-clel 2815  df-nfc 2889  df-ne 2936  df-ral 3055  df-rex 3065  df-reu 3346  df-rab 3393  df-v 3434  df-sbc 3731  df-csb 3839  df-dif 3893  df-un 3895  df-in 3897  df-ss 3907  df-pss 3910  df-nul 4269  df-if 4462  df-pw 4538  df-sn 4563  df-pr 4565  df-op 4569  df-uni 4846  df-iun 4930  df-br 5080  df-opab 5142  df-mpt 5161  df-tr 5187  df-id 5520  df-eprel 5525  df-po 5533  df-so 5534  df-fr 5578  df-we 5580  df-xp 5631  df-rel 5632  df-cnv 5633  df-co 5634  df-dm 5635  df-rn 5636  df-res 5637  df-ima 5638  df-pred 6259  df-ord 6320  df-on 6321  df-lim 6322  df-suc 6323  df-iota 6448  df-fun 6494  df-fn 6495  df-f 6496  df-f1 6497  df-fo 6498  df-f1o 6499  df-fv 6500  df-ov 7366  df-oprab 7367  df-mpo 7368  df-om 7814  df-2nd 7939  df-frecs 8228  df-wrecs 8259  df-recs 8308  df-rdg 8346  df-1o 8402  df-oadd 8406  df-ni 10793  df-pli 10794  df-lti 10796
This theorem is referenced by:  prlem934  10954
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