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Theorem exfzdc 10670
Description: Decidability of the existence of an integer defined by a decidable proposition. (Contributed by Jim Kingdon, 28-Jan-2022.)
Hypotheses
Ref Expression
exfzdc.1 (𝜑 → 𝑀 ∈ ℤ)
exfzdc.2 (𝜑 → 𝑁 ∈ ℤ)
exfzdc.3 ((𝜑 ∧ 𝑛 ∈ (𝑀...𝑁)) → DECID 𝜓)
Assertion
Ref Expression
exfzdc (𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑁)𝜓)
Distinct variable groups:   𝑛,𝑀   𝑛,𝑁   𝜑,𝑛
Allowed substitution hint:   𝜓(𝑛)

Proof of Theorem exfzdc
Dummy variables 𝑤 𝑦 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 exfzdc.1 . . . . 5 (𝜑 → 𝑀 ∈ ℤ)
2 exfzdc.2 . . . . 5 (𝜑 → 𝑁 ∈ ℤ)
3 eluz 9945 . . . . 5 ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑁 ∈ (ℤ≥‘𝑀) ↔ 𝑀 ≤ 𝑁))
41, 2, 3syl2anc 415 . . . 4 (𝜑 → (𝑁 ∈ (ℤ≥‘𝑀) ↔ 𝑀 ≤ 𝑁))
54biimpar 297 . . 3 ((𝜑 ∧ 𝑀 ≤ 𝑁) → 𝑁 ∈ (ℤ≥‘𝑀))
6 simpl 109 . . 3 ((𝜑 ∧ 𝑀 ≤ 𝑁) → 𝜑)
7 eluzfz2 10447 . . . 4 (𝑁 ∈ (ℤ≥‘𝑀) → 𝑁 ∈ (𝑀...𝑁))
8 oveq2 6093 . . . . . . . 8 (𝑤 = 𝑀 → (𝑀...𝑤) = (𝑀...𝑀))
98rexeqdv 2756 . . . . . . 7 (𝑤 = 𝑀 → (∃𝑛 ∈ (𝑀...𝑤)𝜓 ↔ ∃𝑛 ∈ (𝑀...𝑀)𝜓))
109dcbid 850 . . . . . 6 (𝑤 = 𝑀 → (DECID ∃𝑛 ∈ (𝑀...𝑤)𝜓 ↔ DECID ∃𝑛 ∈ (𝑀...𝑀)𝜓))
1110imbi2d 230 . . . . 5 (𝑤 = 𝑀 → ((𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑤)𝜓) ↔ (𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑀)𝜓)))
12 oveq2 6093 . . . . . . . 8 (𝑤 = 𝑦 → (𝑀...𝑤) = (𝑀...𝑦))
1312rexeqdv 2756 . . . . . . 7 (𝑤 = 𝑦 → (∃𝑛 ∈ (𝑀...𝑤)𝜓 ↔ ∃𝑛 ∈ (𝑀...𝑦)𝜓))
1413dcbid 850 . . . . . 6 (𝑤 = 𝑦 → (DECID ∃𝑛 ∈ (𝑀...𝑤)𝜓 ↔ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓))
1514imbi2d 230 . . . . 5 (𝑤 = 𝑦 → ((𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑤)𝜓) ↔ (𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓)))
16 oveq2 6093 . . . . . . . 8 (𝑤 = (𝑦 + 1) → (𝑀...𝑤) = (𝑀...(𝑦 + 1)))
1716rexeqdv 2756 . . . . . . 7 (𝑤 = (𝑦 + 1) → (∃𝑛 ∈ (𝑀...𝑤)𝜓 ↔ ∃𝑛 ∈ (𝑀...(𝑦 + 1))𝜓))
1817dcbid 850 . . . . . 6 (𝑤 = (𝑦 + 1) → (DECID ∃𝑛 ∈ (𝑀...𝑤)𝜓 ↔ DECID ∃𝑛 ∈ (𝑀...(𝑦 + 1))𝜓))
1918imbi2d 230 . . . . 5 (𝑤 = (𝑦 + 1) → ((𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑤)𝜓) ↔ (𝜑 → DECID ∃𝑛 ∈ (𝑀...(𝑦 + 1))𝜓)))
20 oveq2 6093 . . . . . . . 8 (𝑤 = 𝑁 → (𝑀...𝑤) = (𝑀...𝑁))
2120rexeqdv 2756 . . . . . . 7 (𝑤 = 𝑁 → (∃𝑛 ∈ (𝑀...𝑤)𝜓 ↔ ∃𝑛 ∈ (𝑀...𝑁)𝜓))
2221dcbid 850 . . . . . 6 (𝑤 = 𝑁 → (DECID ∃𝑛 ∈ (𝑀...𝑤)𝜓 ↔ DECID ∃𝑛 ∈ (𝑀...𝑁)𝜓))
2322imbi2d 230 . . . . 5 (𝑤 = 𝑁 → ((𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑤)𝜓) ↔ (𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑁)𝜓)))
24 eluzfz1 10446 . . . . . . . . 9 (𝑁 ∈ (ℤ≥‘𝑀) → 𝑀 ∈ (𝑀...𝑁))
2524adantl 277 . . . . . . . 8 ((𝜑 ∧ 𝑁 ∈ (ℤ≥‘𝑀)) → 𝑀 ∈ (𝑀...𝑁))
26 exfzdc.3 . . . . . . . . . 10 ((𝜑 ∧ 𝑛 ∈ (𝑀...𝑁)) → DECID 𝜓)
2726ralrimiva 2623 . . . . . . . . 9 (𝜑 → ∀𝑛 ∈ (𝑀...𝑁)DECID 𝜓)
2827adantr 276 . . . . . . . 8 ((𝜑 ∧ 𝑁 ∈ (ℤ≥‘𝑀)) → ∀𝑛 ∈ (𝑀...𝑁)DECID 𝜓)
29 nfsbc1v 3070 . . . . . . . . . 10 Ⅎ𝑛[𝑀 / 𝑛]𝜓
3029nfdc 1711 . . . . . . . . 9 Ⅎ𝑛DECID [𝑀 / 𝑛]𝜓
31 sbceq1a 3061 . . . . . . . . . 10 (𝑛 = 𝑀 → (𝜓 ↔ [𝑀 / 𝑛]𝜓))
3231dcbid 850 . . . . . . . . 9 (𝑛 = 𝑀 → (DECID 𝜓 ↔ DECID [𝑀 / 𝑛]𝜓))
3330, 32rspc 2923 . . . . . . . 8 (𝑀 ∈ (𝑀...𝑁) → (∀𝑛 ∈ (𝑀...𝑁)DECID 𝜓 → DECID [𝑀 / 𝑛]𝜓))
3425, 28, 33sylc 62 . . . . . . 7 ((𝜑 ∧ 𝑁 ∈ (ℤ≥‘𝑀)) → DECID [𝑀 / 𝑛]𝜓)
351adantr 276 . . . . . . . . . . 11 ((𝜑 ∧ 𝑁 ∈ (ℤ≥‘𝑀)) → 𝑀 ∈ ℤ)
36 fzsn 10483 . . . . . . . . . . 11 (𝑀 ∈ ℤ → (𝑀...𝑀) = {𝑀})
3735, 36syl 14 . . . . . . . . . 10 ((𝜑 ∧ 𝑁 ∈ (ℤ≥‘𝑀)) → (𝑀...𝑀) = {𝑀})
3837rexeqdv 2756 . . . . . . . . 9 ((𝜑 ∧ 𝑁 ∈ (ℤ≥‘𝑀)) → (∃𝑛 ∈ (𝑀...𝑀)𝜓 ↔ ∃𝑛 ∈ {𝑀}𝜓))
39 rexsns 3748 . . . . . . . . 9 (∃𝑛 ∈ {𝑀}𝜓 ↔ [𝑀 / 𝑛]𝜓)
4038, 39bitrdi 196 . . . . . . . 8 ((𝜑 ∧ 𝑁 ∈ (ℤ≥‘𝑀)) → (∃𝑛 ∈ (𝑀...𝑀)𝜓 ↔ [𝑀 / 𝑛]𝜓))
4140dcbid 850 . . . . . . 7 ((𝜑 ∧ 𝑁 ∈ (ℤ≥‘𝑀)) → (DECID ∃𝑛 ∈ (𝑀...𝑀)𝜓 ↔ DECID [𝑀 / 𝑛]𝜓))
4234, 41mpbird 167 . . . . . 6 ((𝜑 ∧ 𝑁 ∈ (ℤ≥‘𝑀)) → DECID ∃𝑛 ∈ (𝑀...𝑀)𝜓)
4342expcom 116 . . . . 5 (𝑁 ∈ (ℤ≥‘𝑀) → (𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑀)𝜓))
44 simpr 110 . . . . . . . . . 10 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓)
45 fzofzp1 10656 . . . . . . . . . . . . 13 (𝑦 ∈ (𝑀..^𝑁) → (𝑦 + 1) ∈ (𝑀...𝑁))
4645ad2antrr 492 . . . . . . . . . . . 12 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → (𝑦 + 1) ∈ (𝑀...𝑁))
4727ad2antlr 493 . . . . . . . . . . . 12 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → ∀𝑛 ∈ (𝑀...𝑁)DECID 𝜓)
48 nfsbc1v 3070 . . . . . . . . . . . . . 14 Ⅎ𝑛[(𝑦 + 1) / 𝑛]𝜓
4948nfdc 1711 . . . . . . . . . . . . 13 Ⅎ𝑛DECID [(𝑦 + 1) / 𝑛]𝜓
50 sbceq1a 3061 . . . . . . . . . . . . . 14 (𝑛 = (𝑦 + 1) → (𝜓 ↔ [(𝑦 + 1) / 𝑛]𝜓))
5150dcbid 850 . . . . . . . . . . . . 13 (𝑛 = (𝑦 + 1) → (DECID 𝜓 ↔ DECID [(𝑦 + 1) / 𝑛]𝜓))
5249, 51rspc 2923 . . . . . . . . . . . 12 ((𝑦 + 1) ∈ (𝑀...𝑁) → (∀𝑛 ∈ (𝑀...𝑁)DECID 𝜓 → DECID [(𝑦 + 1) / 𝑛]𝜓))
5346, 47, 52sylc 62 . . . . . . . . . . 11 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → DECID [(𝑦 + 1) / 𝑛]𝜓)
54 rexsns 3748 . . . . . . . . . . . 12 (∃𝑛 ∈ {(𝑦 + 1)}𝜓 ↔ [(𝑦 + 1) / 𝑛]𝜓)
5554dcbii 852 . . . . . . . . . . 11 (DECID ∃𝑛 ∈ {(𝑦 + 1)}𝜓 ↔ DECID [(𝑦 + 1) / 𝑛]𝜓)
5653, 55sylibr 134 . . . . . . . . . 10 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → DECID ∃𝑛 ∈ {(𝑦 + 1)}𝜓)
57 dcor 948 . . . . . . . . . 10 (DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓 → (DECID ∃𝑛 ∈ {(𝑦 + 1)}𝜓 → DECID (∃𝑛 ∈ (𝑀...𝑦)𝜓 ∨ ∃𝑛 ∈ {(𝑦 + 1)}𝜓)))
5844, 56, 57sylc 62 . . . . . . . . 9 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → DECID (∃𝑛 ∈ (𝑀...𝑦)𝜓 ∨ ∃𝑛 ∈ {(𝑦 + 1)}𝜓))
59 rexun 3409 . . . . . . . . . 10 (∃𝑛 ∈ ((𝑀...𝑦) ∪ {(𝑦 + 1)})𝜓 ↔ (∃𝑛 ∈ (𝑀...𝑦)𝜓 ∨ ∃𝑛 ∈ {(𝑦 + 1)}𝜓))
6059dcbii 852 . . . . . . . . 9 (DECID ∃𝑛 ∈ ((𝑀...𝑦) ∪ {(𝑦 + 1)})𝜓 ↔ DECID (∃𝑛 ∈ (𝑀...𝑦)𝜓 ∨ ∃𝑛 ∈ {(𝑦 + 1)}𝜓))
6158, 60sylibr 134 . . . . . . . 8 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → DECID ∃𝑛 ∈ ((𝑀...𝑦) ∪ {(𝑦 + 1)})𝜓)
62 elfzouz 10569 . . . . . . . . . . . 12 (𝑦 ∈ (𝑀..^𝑁) → 𝑦 ∈ (ℤ≥‘𝑀))
6362ad2antrr 492 . . . . . . . . . . 11 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → 𝑦 ∈ (ℤ≥‘𝑀))
64 fzsuc 10486 . . . . . . . . . . 11 (𝑦 ∈ (ℤ≥‘𝑀) → (𝑀...(𝑦 + 1)) = ((𝑀...𝑦) ∪ {(𝑦 + 1)}))
6563, 64syl 14 . . . . . . . . . 10 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → (𝑀...(𝑦 + 1)) = ((𝑀...𝑦) ∪ {(𝑦 + 1)}))
6665rexeqdv 2756 . . . . . . . . 9 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → (∃𝑛 ∈ (𝑀...(𝑦 + 1))𝜓 ↔ ∃𝑛 ∈ ((𝑀...𝑦) ∪ {(𝑦 + 1)})𝜓))
6766dcbid 850 . . . . . . . 8 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → (DECID ∃𝑛 ∈ (𝑀...(𝑦 + 1))𝜓 ↔ DECID ∃𝑛 ∈ ((𝑀...𝑦) ∪ {(𝑦 + 1)})𝜓))
6861, 67mpbird 167 . . . . . . 7 (((𝑦 ∈ (𝑀..^𝑁) ∧ 𝜑) ∧ DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → DECID ∃𝑛 ∈ (𝑀...(𝑦 + 1))𝜓)
6968exp31 364 . . . . . 6 (𝑦 ∈ (𝑀..^𝑁) → (𝜑 → (DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓 → DECID ∃𝑛 ∈ (𝑀...(𝑦 + 1))𝜓)))
7069a2d 26 . . . . 5 (𝑦 ∈ (𝑀..^𝑁) → ((𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑦)𝜓) → (𝜑 → DECID ∃𝑛 ∈ (𝑀...(𝑦 + 1))𝜓)))
7111, 15, 19, 23, 43, 70fzind2 10669 . . . 4 (𝑁 ∈ (𝑀...𝑁) → (𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑁)𝜓))
727, 71syl 14 . . 3 (𝑁 ∈ (ℤ≥‘𝑀) → (𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑁)𝜓))
735, 6, 72sylc 62 . 2 ((𝜑 ∧ 𝑀 ≤ 𝑁) → DECID ∃𝑛 ∈ (𝑀...𝑁)𝜓)
74 rex0 3539 . . . . 5 ¬ ∃𝑛 ∈ ∅ 𝜓
75 zltnle 9695 . . . . . . . . 9 ((𝑁 ∈ ℤ ∧ 𝑀 ∈ ℤ) → (𝑁 < 𝑀 ↔ ¬ 𝑀 ≤ 𝑁))
762, 1, 75syl2anc 415 . . . . . . . 8 (𝜑 → (𝑁 < 𝑀 ↔ ¬ 𝑀 ≤ 𝑁))
7776biimpar 297 . . . . . . 7 ((𝜑 ∧ ¬ 𝑀 ≤ 𝑁) → 𝑁 < 𝑀)
78 fzn 10457 . . . . . . . . 9 ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑁 < 𝑀 ↔ (𝑀...𝑁) = ∅))
791, 2, 78syl2anc 415 . . . . . . . 8 (𝜑 → (𝑁 < 𝑀 ↔ (𝑀...𝑁) = ∅))
8079adantr 276 . . . . . . 7 ((𝜑 ∧ ¬ 𝑀 ≤ 𝑁) → (𝑁 < 𝑀 ↔ (𝑀...𝑁) = ∅))
8177, 80mpbid 147 . . . . . 6 ((𝜑 ∧ ¬ 𝑀 ≤ 𝑁) → (𝑀...𝑁) = ∅)
8281rexeqdv 2756 . . . . 5 ((𝜑 ∧ ¬ 𝑀 ≤ 𝑁) → (∃𝑛 ∈ (𝑀...𝑁)𝜓 ↔ ∃𝑛 ∈ ∅ 𝜓))
8374, 82mtbiri 686 . . . 4 ((𝜑 ∧ ¬ 𝑀 ≤ 𝑁) → ¬ ∃𝑛 ∈ (𝑀...𝑁)𝜓)
8483olcd 746 . . 3 ((𝜑 ∧ ¬ 𝑀 ≤ 𝑁) → (∃𝑛 ∈ (𝑀...𝑁)𝜓 ∨ ¬ ∃𝑛 ∈ (𝑀...𝑁)𝜓))
85 df-dc 847 . . 3 (DECID ∃𝑛 ∈ (𝑀...𝑁)𝜓 ↔ (∃𝑛 ∈ (𝑀...𝑁)𝜓 ∨ ¬ ∃𝑛 ∈ (𝑀...𝑁)𝜓))
8684, 85sylibr 134 . 2 ((𝜑 ∧ ¬ 𝑀 ≤ 𝑁) → DECID ∃𝑛 ∈ (𝑀...𝑁)𝜓)
87 zdcle 9726 . . . 4 ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → DECID 𝑀 ≤ 𝑁)
88 exmiddc 848 . . . 4 (DECID 𝑀 ≤ 𝑁 → (𝑀 ≤ 𝑁 ∨ ¬ 𝑀 ≤ 𝑁))
8987, 88syl 14 . . 3 ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 ≤ 𝑁 ∨ ¬ 𝑀 ≤ 𝑁))
901, 2, 89syl2anc 415 . 2 (𝜑 → (𝑀 ≤ 𝑁 ∨ ¬ 𝑀 ≤ 𝑁))
9173, 86, 90mpjaodan 810 1 (𝜑 → DECID ∃𝑛 ∈ (𝑀...𝑁)𝜓)
Colors of variables:    wff set class
This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ∧ wa 104   ↔ wb 105   ∨ wo 720  DECID wdc 846   = wceq 1402   ∈ wcel 2209  ∀wral 2528  ∃wrex 2529  [wsbc 3051   ∪ cun 3218  ∅c0 3520  {csn 3709   class class class wbr 4130  ‘cfv 5377  (class class class)co 6085  1c1 8181   + caddc 8183   < clt 8361   ≤ cle 8362  ℤcz 9649  ℤ≥cuz 9931  ...cfz 10422  ..^cfzo 10560
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 623  ax-in2 624  ax-io 721  ax-5 1500  ax-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-8 1557  ax-10 1558  ax-11 1559  ax-i12 1560  ax-bndl 1562  ax-4 1563  ax-17 1579  ax-i9 1583  ax-ial 1587  ax-i5r 1588  ax-14 2212  ax-ext 2220  ax-sep 4249  ax-pow 4311  ax-pr 4346  ax-un 4578  ax-setind 4684  ax-cnex 8271  ax-resscn 8272  ax-1cn 8273  ax-1re 8274  ax-icn 8275  ax-addcl 8276  ax-addrcl 8277  ax-mulcl 8278  ax-addcom 8280  ax-addass 8282  ax-distr 8284  ax-i2m1 8285  ax-0lt1 8286  ax-0id 8288  ax-rnegex 8289  ax-cnre 8291  ax-pre-ltirr 8292  ax-pre-ltwlin 8293  ax-pre-lttrn 8294  ax-pre-apti 8295  ax-pre-ltadd 8296
This proof depends on definitions:  df-bi 117  df-dc 847  df-3or 1010  df-3an 1011  df-tru 1405  df-fal 1408  df-nf 1514  df-sb 1816  df-eu 2089  df-mo 2090  df-clab 2225  df-cleq 2231  df-clel 2234  df-nfc 2381  df-ne 2421  df-nel 2516  df-ral 2533  df-rex 2534  df-reu 2535  df-rab 2537  df-v 2823  df-sbc 3052  df-csb 3148  df-dif 3222  df-un 3224  df-in 3226  df-ss 3233  df-nul 3521  df-pw 3690  df-sn 3715  df-pr 3716  df-op 3718  df-uni 3936  df-int 3971  df-iun 4014  df-br 4131  df-opab 4193  df-mpt 4194  df-id 4438  df-xp 4780  df-rel 4781  df-cnv 4782  df-co 4783  df-dm 4784  df-rn 4785  df-res 4786  df-ima 4787  df-iota 5337  df-fun 5379  df-fn 5380  df-f 5381  df-fv 5385  df-riota 6038  df-ov 6088  df-oprab 6089  df-mpo 6090  df-1st 6374  df-2nd 6375  df-pnf 8363  df-mnf 8364  df-xr 8365  df-ltxr 8366  df-le 8367  df-sub 8501  df-neg 8502  df-inn 9308  df-n0 9569  df-z 9650  df-uz 9932  df-fz 10423  df-fzo 10561
This theorem is used by:  nn0sqdc  11162  prmind2  12917  4sqlemafi  13197  4sqexercise1  13200  4sqexercise2  13201  4sqlemsdc  13202  bpos  16281
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