Users' Mathboxes Mathbox for Jonathan Ben-Naim < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >   Mathboxes  >  bnj110 Structured version   Visualization version   GIF version

Theorem bnj110 35488
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 ↔ ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))
Assertion
Ref Expression
bnj110 ((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ∀𝑥 ∈ 𝐴 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 3089 . . . . 5 (∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ [𝑧 / 𝑥]𝜑 ↔ ¬ ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑)
2 sbcng 3786 . . . . . . . 8 (𝑧 ∈ V → ([𝑧 / 𝑥] ¬ 𝜑 ↔ ¬ [𝑧 / 𝑥]𝜑))
32elv 3456 . . . . . . 7 ([𝑧 / 𝑥] ¬ 𝜑 ↔ ¬ [𝑧 / 𝑥]𝜑)
43bicomi 227 . . . . . 6 (¬ [𝑧 / 𝑥]𝜑 ↔ [𝑧 / 𝑥] ¬ 𝜑)
54ralbii 3109 . . . . 5 (∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ [𝑧 / 𝑥]𝜑 ↔ ∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥] ¬ 𝜑)
61, 5bitr3i 280 . . . 4 (¬ ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑 ↔ ∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥] ¬ 𝜑)
7 df-rab 3414 . . . . . . 7 {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ¬ 𝜑)}
87eleq2i 2853 . . . . . 6 (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ↔ 𝑧 ∈ {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ¬ 𝜑)})
9 df-sbc 3740 . . . . . . 7 ([𝑧 / 𝑥](𝑥 ∈ 𝐴 ∧ ¬ 𝜑) ↔ 𝑧 ∈ {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ¬ 𝜑)})
10 sbcan 3788 . . . . . . . 8 ([𝑧 / 𝑥](𝑥 ∈ 𝐴 ∧ ¬ 𝜑) ↔ ([𝑧 / 𝑥]𝑥 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑))
11 sbcel1v 3804 . . . . . . . . 9 ([𝑧 / 𝑥]𝑥 ∈ 𝐴 ↔ 𝑧 ∈ 𝐴)
1211anbi1i 636 . . . . . . . 8 (([𝑧 / 𝑥]𝑥 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑) ↔ (𝑧 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑))
1310, 12bitri 278 . . . . . . 7 ([𝑧 / 𝑥](𝑥 ∈ 𝐴 ∧ ¬ 𝜑) ↔ (𝑧 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑))
149, 13bitr3i 280 . . . . . 6 (𝑧 ∈ {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ¬ 𝜑)} ↔ (𝑧 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑))
158, 14bitri 278 . . . . 5 (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ↔ (𝑧 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑))
1615simprbi 503 . . . 4 (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → [𝑧 / 𝑥] ¬ 𝜑)
176, 16mprgbir 3084 . . 3 ¬ ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑
18 bnj110.1 . . . . . . . . 9 𝐴 ∈ V
1918rabex 5300 . . . . . . . 8 {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∈ V
2019biantrur 540 . . . . . . 7 (𝑅 Fr 𝐴 ↔ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∈ V ∧ 𝑅 Fr 𝐴))
21 rexnal 3115 . . . . . . . 8 (∃𝑥 ∈ 𝐴 ¬ 𝜑 ↔ ¬ ∀𝑥 ∈ 𝐴 𝜑)
22 rabn0 4339 . . . . . . . . 9 ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅ ↔ ∃𝑥 ∈ 𝐴 ¬ 𝜑)
23 ssrab2 4028 . . . . . . . . . 10 {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴
2423biantrur 540 . . . . . . . . 9 ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅ ↔ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅))
2522, 24bitr3i 280 . . . . . . . 8 (∃𝑥 ∈ 𝐴 ¬ 𝜑 ↔ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅))
2621, 25bitr3i 280 . . . . . . 7 (¬ ∀𝑥 ∈ 𝐴 𝜑 ↔ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅))
27 fri 5609 . . . . . . 7 ((({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∈ V ∧ 𝑅 Fr 𝐴) ∧ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅)) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}∀𝑤 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧)
2820, 26, 27syl2anb 610 . . . . . 6 ((𝑅 Fr 𝐴 ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}∀𝑤 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧)
29 eqid 2761 . . . . . . . 8 {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} = {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}
3029bnj23 35349 . . . . . . 7 (∀𝑤 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧 → ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑))
31 df-ral 3078 . . . . . . . . . 10 (∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)))
3231sbcbii 3795 . . . . . . . . 9 ([𝑧 / 𝑥]∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ [𝑧 / 𝑥]∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)))
33 sbcal 3798 . . . . . . . . . 10 ([𝑧 / 𝑥]∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ∀𝑦[𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)))
34 sbcimg 3787 . . . . . . . . . . . . 13 (𝑧 ∈ V → ([𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ([𝑧 / 𝑥]𝑦 ∈ 𝐴 → [𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))))
3534elv 3456 . . . . . . . . . . . 12 ([𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ([𝑧 / 𝑥]𝑦 ∈ 𝐴 → [𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)))
36 vex 3455 . . . . . . . . . . . . . 14 𝑧 ∈ V
37 nfv 1947 . . . . . . . . . . . . . 14 Ⅎ𝑥 𝑦 ∈ 𝐴
3836, 37sbcgfi 3812 . . . . . . . . . . . . 13 ([𝑧 / 𝑥]𝑦 ∈ 𝐴 ↔ 𝑦 ∈ 𝐴)
39 sbcimg 3787 . . . . . . . . . . . . . . 15 (𝑧 ∈ V → ([𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ ([𝑧 / 𝑥]𝑦𝑅𝑥 → [𝑧 / 𝑥][𝑦 / 𝑥]𝜑)))
4039elv 3456 . . . . . . . . . . . . . 14 ([𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ ([𝑧 / 𝑥]𝑦𝑅𝑥 → [𝑧 / 𝑥][𝑦 / 𝑥]𝜑))
41 sbcbr2g 5163 . . . . . . . . . . . . . . . . 17 (𝑧 ∈ V → ([𝑧 / 𝑥]𝑦𝑅𝑥 ↔ 𝑦𝑅⦋𝑧 / 𝑥⦌𝑥))
4241elv 3456 . . . . . . . . . . . . . . . 16 ([𝑧 / 𝑥]𝑦𝑅𝑥 ↔ 𝑦𝑅⦋𝑧 / 𝑥⦌𝑥)
4336csbvargi 4393 . . . . . . . . . . . . . . . . 17 ⦋𝑧 / 𝑥⦌𝑥 = 𝑧
4443breq2i 5111 . . . . . . . . . . . . . . . 16 (𝑦𝑅⦋𝑧 / 𝑥⦌𝑥 ↔ 𝑦𝑅𝑧)
4542, 44bitri 278 . . . . . . . . . . . . . . 15 ([𝑧 / 𝑥]𝑦𝑅𝑥 ↔ 𝑦𝑅𝑧)
46 nfsbc1v 3759 . . . . . . . . . . . . . . . 16 Ⅎ𝑥[𝑦 / 𝑥]𝜑
4736, 46sbcgfi 3812 . . . . . . . . . . . . . . 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]𝑦 ∈ 𝐴 → [𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ (𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)))
5135, 50bitri 278 . . . . . . . . . . 11 ([𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ (𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)))
5251albii 1852 . . . . . . . . . 10 (∀𝑦[𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)))
5333, 52bitri 278 . . . . . . . . 9 ([𝑧 / 𝑥]∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)))
5432, 53bitri 278 . . . . . . . 8 ([𝑧 / 𝑥]∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)))
55 bnj110.2 . . . . . . . . 9 (𝜓 ↔ ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))
5655sbcbii 3795 . . . . . . . 8 ([𝑧 / 𝑥]𝜓 ↔ [𝑧 / 𝑥]∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))
57 df-ral 3078 . . . . . . . 8 (∀𝑦 ∈ 𝐴 (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)))
5854, 56, 573bitr4i 306 . . . . . . 7 ([𝑧 / 𝑥]𝜓 ↔ ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑))
5930, 58sylibr 237 . . . . . 6 (∀𝑤 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧 → [𝑧 / 𝑥]𝜓)
6028, 59bnj31 35350 . . . . 5 ((𝑅 Fr 𝐴 ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜓)
61 nfv 1947 . . . . . . . 8 Ⅎ𝑧(𝜓 → 𝜑)
62 nfsbc1v 3759 . . . . . . . . 9 Ⅎ𝑥[𝑧 / 𝑥]𝜓
63 nfsbc1v 3759 . . . . . . . . 9 Ⅎ𝑥[𝑧 / 𝑥]𝜑
6462, 63nfim 1929 . . . . . . . 8 Ⅎ𝑥([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑)
65 sbceq1a 3750 . . . . . . . . 9 (𝑥 = 𝑧 → (𝜓 ↔ [𝑧 / 𝑥]𝜓))
66 sbceq1a 3750 . . . . . . . . 9 (𝑥 = 𝑧 → (𝜑 ↔ [𝑧 / 𝑥]𝜑))
6765, 66imbi12d 347 . . . . . . . 8 (𝑥 = 𝑧 → ((𝜓 → 𝜑) ↔ ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑)))
6861, 64, 67cbvralw 3305 . . . . . . 7 (∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ↔ ∀𝑧 ∈ 𝐴 ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑))
69 elrabi 3641 . . . . . . . . 9 (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → 𝑧 ∈ 𝐴)
7069imim1i 64 . . . . . . . 8 ((𝑧 ∈ 𝐴 → ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑)) → (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑)))
7170ralimi2 3095 . . . . . . 7 (∀𝑧 ∈ 𝐴 ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑) → ∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑))
7268, 71sylbi 220 . . . . . 6 (∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) → ∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑))
73 rexim 3104 . . . . . 6 (∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑) → (∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜓 → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑))
7472, 73syl 18 . . . . 5 (∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) → (∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜓 → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑))
7560, 74mpan9 516 . . . 4 (((𝑅 Fr 𝐴 ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑) ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑)
7675an32s 665 . . 3 (((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑)
7717, 76mto 200 . 2 ¬ ((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑)
78 iman 407 . 2 (((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ∀𝑥 ∈ 𝐴 𝜑) ↔ ¬ ((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑))
7977, 78mpbir 234 1 ((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ∀𝑥 ∈ 𝐴 𝜑)
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ↔ wb 209   ∧ wa 401  ∀wal 1568   ∈ wcel 2145  {cab 2739   ≠ wne 2956  ∀wral 3077  ∃wrex 3087  {crab 3413  Vcvv 3451  [wsbc 3739  ⦋csb 3847   ⊆ wss 3899  ∅c0 4279   class class class wbr 5103   Fr wfr 5601
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147  ax-9 2155  ax-10 2178  ax-11 2194  ax-12 2213  ax-ext 2733  ax-sep 5249
This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-clab 2740  df-cleq 2753  df-clel 2836  df-nfc 2910  df-ne 2957  df-ral 3078  df-rex 3088  df-rab 3414  df-v 3453  df-sbc 3740  df-csb 3848  df-dif 3902  df-un 3904  df-in 3906  df-ss 3916  df-nul 4280  df-if 4483  df-pw 4559  df-sn 4585  df-pr 4587  df-op 4591  df-br 5104  df-fr 5604
This theorem is used by:  bnj157  35489  bnj580  35543  bnj1052  35605  bnj1030  35617  bnj1133  35619
  Copyright terms: Public domain W3C validator