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Theorem bnj1204 35642
Description: Well-founded induction. 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.)
Hypothesis
Ref Expression
bnj1204.1 (𝜓 ↔ ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))
Assertion
Ref Expression
bnj1204 ((𝑅 FrSe 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 bnj1204
Dummy variable 𝑧 is distinct from all other variables.
StepHypRef Expression
1 simp1 1154 . . . . . 6 ((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) → 𝑅 FrSe 𝐴)
2 ssrab2 4005 . . . . . . 7 {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴
32a1i 11 . . . . . 6 ((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) → {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴)
4 simp3 1156 . . . . . . 7 ((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) → ∃𝑥 ∈ 𝐴 ¬ 𝜑)
5 rabn0 4338 . . . . . . 7 ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅ ↔ ∃𝑥 ∈ 𝐴 ¬ 𝜑)
64, 5sylibr 237 . . . . . 6 ((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) → {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅)
7 nfrab1 3431 . . . . . . . 8 Ⅎ𝑥{𝑥 ∈ 𝐴 ∣ ¬ 𝜑}
87nfcrii 2917 . . . . . . 7 (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → ∀𝑥 𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑})
98bnj1228 35641 . . . . . 6 ((𝑅 FrSe 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅) → ∃𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥)
101, 3, 6, 9syl3anc 1398 . . . . 5 ((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) → ∃𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥)
11 biid 264 . . . . 5 (((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) ∧ 𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) ↔ ((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) ∧ 𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥))
12 nfv 1946 . . . . . . 7 Ⅎ𝑥 𝑅 FrSe 𝐴
13 nfra1 3286 . . . . . . 7 Ⅎ𝑥∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)
14 nfre1 3287 . . . . . . 7 Ⅎ𝑥∃𝑥 ∈ 𝐴 ¬ 𝜑
1512, 13, 14nf3an 1933 . . . . . 6 Ⅎ𝑥(𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑)
1615nf5ri 2231 . . . . 5 ((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) → ∀𝑥(𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑))
1710, 11, 16bnj1521 35481 . . . 4 ((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) → ∃𝑥((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) ∧ 𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥))
18 eqid 2760 . . . . . 6 {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} = {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}
1918, 11bnj1212 35429 . . . . 5 (((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) ∧ 𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → 𝑥 ∈ 𝐴)
20 nfra1 3286 . . . . . . . 8 Ⅎ𝑦∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥
21 simp3 1156 . . . . . . . . . . . . . . 15 ((𝑦 ∈ 𝐴 ∧ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥)
2221bnj1211 35427 . . . . . . . . . . . . . 14 ((𝑦 ∈ 𝐴 ∧ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → ∀𝑦(𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → ¬ 𝑦𝑅𝑥))
23 con2b 362 . . . . . . . . . . . . . . 15 ((𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → ¬ 𝑦𝑅𝑥) ↔ (𝑦𝑅𝑥 → ¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}))
2423albii 1851 . . . . . . . . . . . . . 14 (∀𝑦(𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → ¬ 𝑦𝑅𝑥) ↔ ∀𝑦(𝑦𝑅𝑥 → ¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}))
2522, 24sylib 221 . . . . . . . . . . . . 13 ((𝑦 ∈ 𝐴 ∧ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → ∀𝑦(𝑦𝑅𝑥 → ¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}))
26 simp2 1155 . . . . . . . . . . . . 13 ((𝑦 ∈ 𝐴 ∧ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → 𝑦𝑅𝑥)
27 sp 2219 . . . . . . . . . . . . 13 (∀𝑦(𝑦𝑅𝑥 → ¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}) → (𝑦𝑅𝑥 → ¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}))
2825, 26, 27sylc 66 . . . . . . . . . . . 12 ((𝑦 ∈ 𝐴 ∧ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → ¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑})
29 simp1 1154 . . . . . . . . . . . 12 ((𝑦 ∈ 𝐴 ∧ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → 𝑦 ∈ 𝐴)
30 nfcv 2922 . . . . . . . . . . . . . . . . . 18 Ⅎ𝑥𝐴
3130elrabsf 3783 . . . . . . . . . . . . . . . . 17 (𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ↔ (𝑦 ∈ 𝐴 ∧ [𝑦 / 𝑥] ¬ 𝜑))
32 vex 3454 . . . . . . . . . . . . . . . . . . 19 𝑦 ∈ V
33 sbcng 3785 . . . . . . . . . . . . . . . . . . 19 (𝑦 ∈ V → ([𝑦 / 𝑥] ¬ 𝜑 ↔ ¬ [𝑦 / 𝑥]𝜑))
3432, 33ax-mp 5 . . . . . . . . . . . . . . . . . 18 ([𝑦 / 𝑥] ¬ 𝜑 ↔ ¬ [𝑦 / 𝑥]𝜑)
3534anbi2i 635 . . . . . . . . . . . . . . . . 17 ((𝑦 ∈ 𝐴 ∧ [𝑦 / 𝑥] ¬ 𝜑) ↔ (𝑦 ∈ 𝐴 ∧ ¬ [𝑦 / 𝑥]𝜑))
3631, 35bitri 278 . . . . . . . . . . . . . . . 16 (𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ↔ (𝑦 ∈ 𝐴 ∧ ¬ [𝑦 / 𝑥]𝜑))
3736notbii 323 . . . . . . . . . . . . . . 15 (¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ↔ ¬ (𝑦 ∈ 𝐴 ∧ ¬ [𝑦 / 𝑥]𝜑))
38 imnan 405 . . . . . . . . . . . . . . 15 ((𝑦 ∈ 𝐴 → ¬ ¬ [𝑦 / 𝑥]𝜑) ↔ ¬ (𝑦 ∈ 𝐴 ∧ ¬ [𝑦 / 𝑥]𝜑))
3937, 38sylbb2 241 . . . . . . . . . . . . . 14 (¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → (𝑦 ∈ 𝐴 → ¬ ¬ [𝑦 / 𝑥]𝜑))
4039imp 412 . . . . . . . . . . . . 13 ((¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ 𝑦 ∈ 𝐴) → ¬ ¬ [𝑦 / 𝑥]𝜑)
4140notnotrd 134 . . . . . . . . . . . 12 ((¬ 𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ 𝑦 ∈ 𝐴) → [𝑦 / 𝑥]𝜑)
4228, 29, 41syl2anc 596 . . . . . . . . . . 11 ((𝑦 ∈ 𝐴 ∧ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → [𝑦 / 𝑥]𝜑)
43423expa 1136 . . . . . . . . . 10 (((𝑦 ∈ 𝐴 ∧ 𝑦𝑅𝑥) ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → [𝑦 / 𝑥]𝜑)
4443expcom 419 . . . . . . . . 9 (∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥 → ((𝑦 ∈ 𝐴 ∧ 𝑦𝑅𝑥) → [𝑦 / 𝑥]𝜑))
4544expd 421 . . . . . . . 8 (∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥 → (𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)))
4620, 45ralrimi 3260 . . . . . . 7 (∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥 → ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))
47 bnj1204.1 . . . . . . 7 (𝜓 ↔ ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))
4846, 47sylibr 237 . . . . . 6 (∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥 → 𝜓)
49483ad2ant3 1153 . . . . 5 (((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) ∧ 𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → 𝜓)
50 simp12 1223 . . . . 5 (((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) ∧ 𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑))
51 simp3 1156 . . . . . . 7 ((𝑥 ∈ 𝐴 ∧ 𝜓 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑))
5251bnj1211 35427 . . . . . 6 ((𝑥 ∈ 𝐴 ∧ 𝜓 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ∀𝑥(𝑥 ∈ 𝐴 → (𝜓 → 𝜑)))
53 simp1 1154 . . . . . 6 ((𝑥 ∈ 𝐴 ∧ 𝜓 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → 𝑥 ∈ 𝐴)
54 simp2 1155 . . . . . 6 ((𝑥 ∈ 𝐴 ∧ 𝜓 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → 𝜓)
55 sp 2219 . . . . . 6 (∀𝑥(𝑥 ∈ 𝐴 → (𝜓 → 𝜑)) → (𝑥 ∈ 𝐴 → (𝜓 → 𝜑)))
5652, 53, 54, 55syl3c 67 . . . . 5 ((𝑥 ∈ 𝐴 ∧ 𝜓 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → 𝜑)
5719, 49, 50, 56syl3anc 1398 . . . 4 (((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) ∧ 𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → 𝜑)
58 rabid 3432 . . . . . 6 (𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ↔ (𝑥 ∈ 𝐴 ∧ ¬ 𝜑))
5958simprbi 503 . . . . 5 (𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → ¬ 𝜑)
60593ad2ant2 1152 . . . 4 (((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑) ∧ 𝑥 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∧ ∀𝑦 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑦𝑅𝑥) → ¬ 𝜑)
6117, 57, 60bnj1304 35449 . . 3 ¬ (𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑) ∧ ∃𝑥 ∈ 𝐴 ¬ 𝜑)
6261bnj1224 35431 . 2 ((𝑅 FrSe 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ¬ ∃𝑥 ∈ 𝐴 ¬ 𝜑)
63 dfral2 3113 . 2 (∀𝑥 ∈ 𝐴 𝜑 ↔ ¬ ∃𝑥 ∈ 𝐴 ¬ 𝜑)
6462, 63sylibr 237 1 ((𝑅 FrSe 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   ∧ w3a 1103  ∀wal 1567   ∈ wcel 2144   ≠ wne 2955  ∀wral 3076  ∃wrex 3086  {crab 3412  Vcvv 3450  [wsbc 3738   ⊆ wss 3895  ∅c0 4278   class class class wbr 5102   FrSe w-bnj15 35323
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1827  ax-4 1841  ax-5 1942  ax-6 1999  ax-7 2040  ax-8 2146  ax-9 2154  ax-10 2177  ax-11 2193  ax-12 2212  ax-ext 2732  ax-rep 5231  ax-sep 5248  ax-nul 5259  ax-pow 5326  ax-pr 5390  ax-un 7751  ax-reg 9586  ax-inf2 9642
This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3or 1104  df-3an 1105  df-tru 1572  df-fal 1582  df-ex 1812  df-nf 1816  df-sb 2099  df-mo 2564  df-eu 2594  df-clab 2739  df-cleq 2752  df-clel 2835  df-nfc 2909  df-ne 2956  df-ral 3077  df-rex 3087  df-reu 3366  df-rab 3413  df-v 3452  df-sbc 3739  df-csb 3847  df-ss 3896  df-pss 4014  df-dif 4047  df-in 4091  df-un 4151  df-nul 4279  df-if 4482  df-pw 4558  df-sn 4584  df-pr 4586  df-op 4590  df-uni 4867  df-iun 4952  df-br 5103  df-opab 5167  df-mpt 5186  df-tr 5212  df-id 5545  df-eprel 5550  df-po 5558  df-so 5559  df-fr 5603  df-we 5605  df-xp 5656  df-rel 5657  df-cnv 5658  df-co 5659  df-dm 5660  df-rn 5661  df-res 5662  df-ima 5663  df-ord 6365  df-on 6366  df-lim 6367  df-suc 6368  df-iota 6494  df-fun 6540  df-fn 6541  df-f 6542  df-f1 6543  df-fo 6544  df-f1o 6545  df-fv 6546  df-om 7878  df-1o 8476  df-bnj17 35318  df-bnj14 35320  df-bnj13 35322  df-bnj15 35324  df-bnj18 35326  df-bnj19 35328
This theorem is used by:  bnj1417  35671
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