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Theorem bnj110 35191
Description: Well-founded induction restricted to a set (𝐴 ∈ V). The proof has been taken from Chapter 4 of Don Monk's notes on Set Theory. See http://euclid.colorado.edu/~monkd/setth.pdf. (Contributed by Jonathan Ben-Naim, 3-Jun-2011.) (New usage is discouraged.)
Hypotheses
Ref Expression
bnj110.1 𝐴 ∈ V
bnj110.2 (𝜓 ↔ ∀𝑦𝐴 (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑))
Assertion
Ref Expression
bnj110 ((𝑅 Fr 𝐴 ∧ ∀𝑥𝐴 (𝜓𝜑)) → ∀𝑥𝐴 𝜑)
Distinct variable groups:   𝑥,𝐴,𝑦   𝑥,𝑅,𝑦   𝜑,𝑦
Allowed substitution hints:   𝜑(𝑥)   𝜓(𝑥,𝑦)

Proof of Theorem bnj110
Dummy variables 𝑧 𝑤 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 ralnex 3097 . . . . 5 (∀𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ¬ [𝑧 / 𝑥]𝜑 ↔ ¬ ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑)
2 sbcng 3800 . . . . . . . 8 (𝑧 ∈ V → ([𝑧 / 𝑥] ¬ 𝜑 ↔ ¬ [𝑧 / 𝑥]𝜑))
32elv 3468 . . . . . . 7 ([𝑧 / 𝑥] ¬ 𝜑 ↔ ¬ [𝑧 / 𝑥]𝜑)
43bicomi 227 . . . . . 6 [𝑧 / 𝑥]𝜑[𝑧 / 𝑥] ¬ 𝜑)
54ralbii 3117 . . . . 5 (∀𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ¬ [𝑧 / 𝑥]𝜑 ↔ ∀𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥] ¬ 𝜑)
61, 5bitr3i 280 . . . 4 (¬ ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑 ↔ ∀𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥] ¬ 𝜑)
7 df-rab 3424 . . . . . . 7 {𝑥𝐴 ∣ ¬ 𝜑} = {𝑥 ∣ (𝑥𝐴 ∧ ¬ 𝜑)}
87eleq2i 2861 . . . . . 6 (𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ↔ 𝑧 ∈ {𝑥 ∣ (𝑥𝐴 ∧ ¬ 𝜑)})
9 df-sbc 3754 . . . . . . 7 ([𝑧 / 𝑥](𝑥𝐴 ∧ ¬ 𝜑) ↔ 𝑧 ∈ {𝑥 ∣ (𝑥𝐴 ∧ ¬ 𝜑)})
10 sbcan 3802 . . . . . . . 8 ([𝑧 / 𝑥](𝑥𝐴 ∧ ¬ 𝜑) ↔ ([𝑧 / 𝑥]𝑥𝐴[𝑧 / 𝑥] ¬ 𝜑))
11 sbcel1v 3818 . . . . . . . . 9 ([𝑧 / 𝑥]𝑥𝐴𝑧𝐴)
1211anbi1i 635 . . . . . . . 8 (([𝑧 / 𝑥]𝑥𝐴[𝑧 / 𝑥] ¬ 𝜑) ↔ (𝑧𝐴[𝑧 / 𝑥] ¬ 𝜑))
1310, 12bitri 278 . . . . . . 7 ([𝑧 / 𝑥](𝑥𝐴 ∧ ¬ 𝜑) ↔ (𝑧𝐴[𝑧 / 𝑥] ¬ 𝜑))
149, 13bitr3i 280 . . . . . 6 (𝑧 ∈ {𝑥 ∣ (𝑥𝐴 ∧ ¬ 𝜑)} ↔ (𝑧𝐴[𝑧 / 𝑥] ¬ 𝜑))
158, 14bitri 278 . . . . 5 (𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ↔ (𝑧𝐴[𝑧 / 𝑥] ¬ 𝜑))
1615simprbi 502 . . . 4 (𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} → [𝑧 / 𝑥] ¬ 𝜑)
176, 16mprgbir 3092 . . 3 ¬ ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑
18 bnj110.1 . . . . . . . . 9 𝐴 ∈ V
1918rabex 5310 . . . . . . . 8 {𝑥𝐴 ∣ ¬ 𝜑} ∈ V
2019biantrur 539 . . . . . . 7 (𝑅 Fr 𝐴 ↔ ({𝑥𝐴 ∣ ¬ 𝜑} ∈ V ∧ 𝑅 Fr 𝐴))
21 rexnal 3123 . . . . . . . 8 (∃𝑥𝐴 ¬ 𝜑 ↔ ¬ ∀𝑥𝐴 𝜑)
22 rabn0 4353 . . . . . . . . 9 ({𝑥𝐴 ∣ ¬ 𝜑} ≠ ∅ ↔ ∃𝑥𝐴 ¬ 𝜑)
23 ssrab2 4042 . . . . . . . . . 10 {𝑥𝐴 ∣ ¬ 𝜑} ⊆ 𝐴
2423biantrur 539 . . . . . . . . 9 ({𝑥𝐴 ∣ ¬ 𝜑} ≠ ∅ ↔ ({𝑥𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥𝐴 ∣ ¬ 𝜑} ≠ ∅))
2522, 24bitr3i 280 . . . . . . . 8 (∃𝑥𝐴 ¬ 𝜑 ↔ ({𝑥𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥𝐴 ∣ ¬ 𝜑} ≠ ∅))
2621, 25bitr3i 280 . . . . . . 7 (¬ ∀𝑥𝐴 𝜑 ↔ ({𝑥𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥𝐴 ∣ ¬ 𝜑} ≠ ∅))
27 fri 5620 . . . . . . 7 ((({𝑥𝐴 ∣ ¬ 𝜑} ∈ V ∧ 𝑅 Fr 𝐴) ∧ ({𝑥𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥𝐴 ∣ ¬ 𝜑} ≠ ∅)) → ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}∀𝑤 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧)
2820, 26, 27syl2anb 609 . . . . . 6 ((𝑅 Fr 𝐴 ∧ ¬ ∀𝑥𝐴 𝜑) → ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}∀𝑤 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧)
29 eqid 2769 . . . . . . . 8 {𝑥𝐴 ∣ ¬ 𝜑} = {𝑥𝐴 ∣ ¬ 𝜑}
3029bnj23 35052 . . . . . . 7 (∀𝑤 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧 → ∀𝑦𝐴 (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑))
31 df-ral 3086 . . . . . . . . . 10 (∀𝑦𝐴 (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑) ↔ ∀𝑦(𝑦𝐴 → (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)))
3231sbcbii 3809 . . . . . . . . 9 ([𝑧 / 𝑥]𝑦𝐴 (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑) ↔ [𝑧 / 𝑥]𝑦(𝑦𝐴 → (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)))
33 sbcal 3812 . . . . . . . . . 10 ([𝑧 / 𝑥]𝑦(𝑦𝐴 → (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)) ↔ ∀𝑦[𝑧 / 𝑥](𝑦𝐴 → (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)))
34 sbcimg 3801 . . . . . . . . . . . . 13 (𝑧 ∈ V → ([𝑧 / 𝑥](𝑦𝐴 → (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)) ↔ ([𝑧 / 𝑥]𝑦𝐴[𝑧 / 𝑥](𝑦𝑅𝑥[𝑦 / 𝑥]𝜑))))
3534elv 3468 . . . . . . . . . . . 12 ([𝑧 / 𝑥](𝑦𝐴 → (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)) ↔ ([𝑧 / 𝑥]𝑦𝐴[𝑧 / 𝑥](𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)))
36 vex 3467 . . . . . . . . . . . . . 14 𝑧 ∈ V
37 nfv 1941 . . . . . . . . . . . . . 14 𝑥 𝑦𝐴
3836, 37sbcgfi 3826 . . . . . . . . . . . . 13 ([𝑧 / 𝑥]𝑦𝐴𝑦𝐴)
39 sbcimg 3801 . . . . . . . . . . . . . . 15 (𝑧 ∈ V → ([𝑧 / 𝑥](𝑦𝑅𝑥[𝑦 / 𝑥]𝜑) ↔ ([𝑧 / 𝑥]𝑦𝑅𝑥[𝑧 / 𝑥][𝑦 / 𝑥]𝜑)))
4039elv 3468 . . . . . . . . . . . . . 14 ([𝑧 / 𝑥](𝑦𝑅𝑥[𝑦 / 𝑥]𝜑) ↔ ([𝑧 / 𝑥]𝑦𝑅𝑥[𝑧 / 𝑥][𝑦 / 𝑥]𝜑))
41 sbcbr2g 5173 . . . . . . . . . . . . . . . . 17 (𝑧 ∈ V → ([𝑧 / 𝑥]𝑦𝑅𝑥𝑦𝑅𝑧 / 𝑥𝑥))
4241elv 3468 . . . . . . . . . . . . . . . 16 ([𝑧 / 𝑥]𝑦𝑅𝑥𝑦𝑅𝑧 / 𝑥𝑥)
4336csbvargi 4406 . . . . . . . . . . . . . . . . 17 𝑧 / 𝑥𝑥 = 𝑧
4443breq2i 5121 . . . . . . . . . . . . . . . 16 (𝑦𝑅𝑧 / 𝑥𝑥𝑦𝑅𝑧)
4542, 44bitri 278 . . . . . . . . . . . . . . 15 ([𝑧 / 𝑥]𝑦𝑅𝑥𝑦𝑅𝑧)
46 nfsbc1v 3773 . . . . . . . . . . . . . . . 16 𝑥[𝑦 / 𝑥]𝜑
4736, 46sbcgfi 3826 . . . . . . . . . . . . . . 15 ([𝑧 / 𝑥][𝑦 / 𝑥]𝜑[𝑦 / 𝑥]𝜑)
4845, 47imbi12i 353 . . . . . . . . . . . . . 14 (([𝑧 / 𝑥]𝑦𝑅𝑥[𝑧 / 𝑥][𝑦 / 𝑥]𝜑) ↔ (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑))
4940, 48bitri 278 . . . . . . . . . . . . 13 ([𝑧 / 𝑥](𝑦𝑅𝑥[𝑦 / 𝑥]𝜑) ↔ (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑))
5038, 49imbi12i 353 . . . . . . . . . . . 12 (([𝑧 / 𝑥]𝑦𝐴[𝑧 / 𝑥](𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)) ↔ (𝑦𝐴 → (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑)))
5135, 50bitri 278 . . . . . . . . . . 11 ([𝑧 / 𝑥](𝑦𝐴 → (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)) ↔ (𝑦𝐴 → (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑)))
5251albii 1846 . . . . . . . . . 10 (∀𝑦[𝑧 / 𝑥](𝑦𝐴 → (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)) ↔ ∀𝑦(𝑦𝐴 → (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑)))
5333, 52bitri 278 . . . . . . . . 9 ([𝑧 / 𝑥]𝑦(𝑦𝐴 → (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑)) ↔ ∀𝑦(𝑦𝐴 → (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑)))
5432, 53bitri 278 . . . . . . . 8 ([𝑧 / 𝑥]𝑦𝐴 (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑) ↔ ∀𝑦(𝑦𝐴 → (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑)))
55 bnj110.2 . . . . . . . . 9 (𝜓 ↔ ∀𝑦𝐴 (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑))
5655sbcbii 3809 . . . . . . . 8 ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝑦𝐴 (𝑦𝑅𝑥[𝑦 / 𝑥]𝜑))
57 df-ral 3086 . . . . . . . 8 (∀𝑦𝐴 (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑) ↔ ∀𝑦(𝑦𝐴 → (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑)))
5854, 56, 573bitr4i 306 . . . . . . 7 ([𝑧 / 𝑥]𝜓 ↔ ∀𝑦𝐴 (𝑦𝑅𝑧[𝑦 / 𝑥]𝜑))
5930, 58sylibr 237 . . . . . 6 (∀𝑤 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧[𝑧 / 𝑥]𝜓)
6028, 59bnj31 35053 . . . . 5 ((𝑅 Fr 𝐴 ∧ ¬ ∀𝑥𝐴 𝜑) → ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜓)
61 nfv 1941 . . . . . . . 8 𝑧(𝜓𝜑)
62 nfsbc1v 3773 . . . . . . . . 9 𝑥[𝑧 / 𝑥]𝜓
63 nfsbc1v 3773 . . . . . . . . 9 𝑥[𝑧 / 𝑥]𝜑
6462, 63nfim 1923 . . . . . . . 8 𝑥([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜑)
65 sbceq1a 3764 . . . . . . . . 9 (𝑥 = 𝑧 → (𝜓[𝑧 / 𝑥]𝜓))
66 sbceq1a 3764 . . . . . . . . 9 (𝑥 = 𝑧 → (𝜑[𝑧 / 𝑥]𝜑))
6765, 66imbi12d 347 . . . . . . . 8 (𝑥 = 𝑧 → ((𝜓𝜑) ↔ ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜑)))
6861, 64, 67cbvralw 3313 . . . . . . 7 (∀𝑥𝐴 (𝜓𝜑) ↔ ∀𝑧𝐴 ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜑))
69 elrabi 3655 . . . . . . . . 9 (𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} → 𝑧𝐴)
7069imim1i 64 . . . . . . . 8 ((𝑧𝐴 → ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜑)) → (𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} → ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜑)))
7170ralimi2 3103 . . . . . . 7 (∀𝑧𝐴 ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜑) → ∀𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜑))
7268, 71sylbi 220 . . . . . 6 (∀𝑥𝐴 (𝜓𝜑) → ∀𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜑))
73 rexim 3112 . . . . . 6 (∀𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑} ([𝑧 / 𝑥]𝜓[𝑧 / 𝑥]𝜑) → (∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜓 → ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑))
7472, 73syl 18 . . . . 5 (∀𝑥𝐴 (𝜓𝜑) → (∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜓 → ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑))
7560, 74mpan9 515 . . . 4 (((𝑅 Fr 𝐴 ∧ ¬ ∀𝑥𝐴 𝜑) ∧ ∀𝑥𝐴 (𝜓𝜑)) → ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑)
7675an32s 664 . . 3 (((𝑅 Fr 𝐴 ∧ ∀𝑥𝐴 (𝜓𝜑)) ∧ ¬ ∀𝑥𝐴 𝜑) → ∃𝑧 ∈ {𝑥𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑)
7717, 76mto 200 . 2 ¬ ((𝑅 Fr 𝐴 ∧ ∀𝑥𝐴 (𝜓𝜑)) ∧ ¬ ∀𝑥𝐴 𝜑)
78 iman 406 . 2 (((𝑅 Fr 𝐴 ∧ ∀𝑥𝐴 (𝜓𝜑)) → ∀𝑥𝐴 𝜑) ↔ ¬ ((𝑅 Fr 𝐴 ∧ ∀𝑥𝐴 (𝜓𝜑)) ∧ ¬ ∀𝑥𝐴 𝜑))
7977, 78mpbir 234 1 ((𝑅 Fr 𝐴 ∧ ∀𝑥𝐴 (𝜓𝜑)) → ∀𝑥𝐴 𝜑)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 209  wa 400  wal 1565  wcel 2149  {cab 2747  wne 2964  wral 3085  wrex 3095  {crab 3423  Vcvv 3463  [wsbc 3753  csb 3861  wss 3913  c0 4294   class class class wbr 5113   Fr wfr 5612
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1822  ax-4 1836  ax-5 1937  ax-6 1994  ax-7 2035  ax-8 2151  ax-9 2159  ax-10 2182  ax-11 2198  ax-12 2219  ax-ext 2741  ax-sep 5261
This theorem depends on definitions:  df-bi 210  df-an 401  df-or 861  df-3an 1103  df-tru 1570  df-fal 1580  df-ex 1807  df-nf 1811  df-sb 2098  df-clab 2748  df-cleq 2761  df-clel 2844  df-nfc 2918  df-ne 2965  df-ral 3086  df-rex 3096  df-rab 3424  df-v 3465  df-sbc 3754  df-csb 3862  df-dif 3916  df-un 3918  df-in 3920  df-ss 3930  df-nul 4295  df-if 4493  df-pw 4569  df-sn 4595  df-pr 4597  df-op 4601  df-br 5114  df-fr 5615
This theorem is referenced by:  bnj157  35192  bnj580  35246  bnj1052  35308  bnj1030  35320  bnj1133  35322
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