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Mirrors > Home > ILE Home > Th. List > nnmindc | GIF version |
Description: An inhabited decidable subset of the natural numbers has a minimum. (Contributed by Jim Kingdon, 23-Sep-2024.) |
Ref | Expression |
---|---|
nnmindc | ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 ∈ 𝐴) → inf(𝐴, ℝ, < ) ∈ 𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 1zzd 9199 | . . . . . 6 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) → 1 ∈ ℤ) | |
2 | eqid 2157 | . . . . . 6 ⊢ {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴} = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴} | |
3 | simpr 109 | . . . . . . 7 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) → 𝑦 ∈ 𝐴) | |
4 | dfss5 3313 | . . . . . . . . . 10 ⊢ (𝐴 ⊆ ℕ ↔ 𝐴 = (ℕ ∩ 𝐴)) | |
5 | 4 | biimpi 119 | . . . . . . . . 9 ⊢ (𝐴 ⊆ ℕ → 𝐴 = (ℕ ∩ 𝐴)) |
6 | nnuz 9479 | . . . . . . . . . . 11 ⊢ ℕ = (ℤ≥‘1) | |
7 | 6 | ineq1i 3305 | . . . . . . . . . 10 ⊢ (ℕ ∩ 𝐴) = ((ℤ≥‘1) ∩ 𝐴) |
8 | dfin5 3109 | . . . . . . . . . 10 ⊢ ((ℤ≥‘1) ∩ 𝐴) = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴} | |
9 | 7, 8 | eqtri 2178 | . . . . . . . . 9 ⊢ (ℕ ∩ 𝐴) = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴} |
10 | 5, 9 | eqtrdi 2206 | . . . . . . . 8 ⊢ (𝐴 ⊆ ℕ → 𝐴 = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}) |
11 | 10 | ad2antrr 480 | . . . . . . 7 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) → 𝐴 = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}) |
12 | 3, 11 | eleqtrd 2236 | . . . . . 6 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) → 𝑦 ∈ {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}) |
13 | eleq1w 2218 | . . . . . . . 8 ⊢ (𝑥 = 𝑛 → (𝑥 ∈ 𝐴 ↔ 𝑛 ∈ 𝐴)) | |
14 | 13 | dcbid 824 | . . . . . . 7 ⊢ (𝑥 = 𝑛 → (DECID 𝑥 ∈ 𝐴 ↔ DECID 𝑛 ∈ 𝐴)) |
15 | simpllr 524 | . . . . . . 7 ⊢ ((((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) ∧ 𝑛 ∈ (1...𝑦)) → ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) | |
16 | elfznn 9962 | . . . . . . . 8 ⊢ (𝑛 ∈ (1...𝑦) → 𝑛 ∈ ℕ) | |
17 | 16 | adantl 275 | . . . . . . 7 ⊢ ((((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) ∧ 𝑛 ∈ (1...𝑦)) → 𝑛 ∈ ℕ) |
18 | 14, 15, 17 | rspcdva 2821 | . . . . . 6 ⊢ ((((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) ∧ 𝑛 ∈ (1...𝑦)) → DECID 𝑛 ∈ 𝐴) |
19 | 1, 2, 12, 18 | infssuzcldc 11850 | . . . . 5 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) → inf({𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}, ℝ, < ) ∈ {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}) |
20 | 11 | infeq1d 6958 | . . . . 5 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) → inf(𝐴, ℝ, < ) = inf({𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}, ℝ, < )) |
21 | 19, 20, 11 | 3eltr4d 2241 | . . . 4 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) ∧ 𝑦 ∈ 𝐴) → inf(𝐴, ℝ, < ) ∈ 𝐴) |
22 | 21 | ex 114 | . . 3 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) → (𝑦 ∈ 𝐴 → inf(𝐴, ℝ, < ) ∈ 𝐴)) |
23 | 22 | exlimdv 1799 | . 2 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴) → (∃𝑦 𝑦 ∈ 𝐴 → inf(𝐴, ℝ, < ) ∈ 𝐴)) |
24 | 23 | 3impia 1182 | 1 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ ∃𝑦 𝑦 ∈ 𝐴) → inf(𝐴, ℝ, < ) ∈ 𝐴) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 DECID wdc 820 ∧ w3a 963 = wceq 1335 ∃wex 1472 ∈ wcel 2128 ∀wral 2435 {crab 2439 ∩ cin 3101 ⊆ wss 3102 ‘cfv 5172 (class class class)co 5826 infcinf 6929 ℝcr 7733 1c1 7735 < clt 7914 ℕcn 8838 ℤ≥cuz 9444 ...cfz 9918 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 604 ax-in2 605 ax-io 699 ax-5 1427 ax-7 1428 ax-gen 1429 ax-ie1 1473 ax-ie2 1474 ax-8 1484 ax-10 1485 ax-11 1486 ax-i12 1487 ax-bndl 1489 ax-4 1490 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-13 2130 ax-14 2131 ax-ext 2139 ax-sep 4084 ax-pow 4137 ax-pr 4171 ax-un 4395 ax-setind 4498 ax-cnex 7825 ax-resscn 7826 ax-1cn 7827 ax-1re 7828 ax-icn 7829 ax-addcl 7830 ax-addrcl 7831 ax-mulcl 7832 ax-addcom 7834 ax-addass 7836 ax-distr 7838 ax-i2m1 7839 ax-0lt1 7840 ax-0id 7842 ax-rnegex 7843 ax-cnre 7845 ax-pre-ltirr 7846 ax-pre-ltwlin 7847 ax-pre-lttrn 7848 ax-pre-apti 7849 ax-pre-ltadd 7850 |
This theorem depends on definitions: df-bi 116 df-dc 821 df-3or 964 df-3an 965 df-tru 1338 df-fal 1341 df-nf 1441 df-sb 1743 df-eu 2009 df-mo 2010 df-clab 2144 df-cleq 2150 df-clel 2153 df-nfc 2288 df-ne 2328 df-nel 2423 df-ral 2440 df-rex 2441 df-reu 2442 df-rmo 2443 df-rab 2444 df-v 2714 df-sbc 2938 df-csb 3032 df-dif 3104 df-un 3106 df-in 3108 df-ss 3115 df-pw 3546 df-sn 3567 df-pr 3568 df-op 3570 df-uni 3775 df-int 3810 df-iun 3853 df-br 3968 df-opab 4028 df-mpt 4029 df-id 4255 df-po 4258 df-iso 4259 df-xp 4594 df-rel 4595 df-cnv 4596 df-co 4597 df-dm 4598 df-rn 4599 df-res 4600 df-ima 4601 df-iota 5137 df-fun 5174 df-fn 5175 df-f 5176 df-f1 5177 df-fo 5178 df-f1o 5179 df-fv 5180 df-isom 5181 df-riota 5782 df-ov 5829 df-oprab 5830 df-mpo 5831 df-1st 6090 df-2nd 6091 df-sup 6930 df-inf 6931 df-pnf 7916 df-mnf 7917 df-xr 7918 df-ltxr 7919 df-le 7920 df-sub 8052 df-neg 8053 df-inn 8839 df-n0 9096 df-z 9173 df-uz 9445 df-fz 9919 df-fzo 10051 |
This theorem is referenced by: nninfdclemcl 12249 nninfdclemp1 12251 |
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