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Mirrors > Home > ILE Home > Th. List > nn0lt2 | GIF version |
Description: A nonnegative integer less than 2 must be 0 or 1. (Contributed by Alexander van der Vekens, 16-Sep-2018.) |
Ref | Expression |
---|---|
nn0lt2 | ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 = 0 ∨ 𝑁 = 1)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | olc 701 | . . 3 ⊢ (𝑁 = 1 → (𝑁 = 0 ∨ 𝑁 = 1)) | |
2 | 1 | a1i 9 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 = 1 → (𝑁 = 0 ∨ 𝑁 = 1))) |
3 | nn0z 9202 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℤ) | |
4 | 2z 9210 | . . . . . 6 ⊢ 2 ∈ ℤ | |
5 | zltlem1 9239 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 2 ∈ ℤ) → (𝑁 < 2 ↔ 𝑁 ≤ (2 − 1))) | |
6 | 3, 4, 5 | sylancl 410 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 2 ↔ 𝑁 ≤ (2 − 1))) |
7 | 2m1e1 8966 | . . . . . 6 ⊢ (2 − 1) = 1 | |
8 | 7 | breq2i 3984 | . . . . 5 ⊢ (𝑁 ≤ (2 − 1) ↔ 𝑁 ≤ 1) |
9 | 6, 8 | bitrdi 195 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 2 ↔ 𝑁 ≤ 1)) |
10 | necom 2418 | . . . . 5 ⊢ (𝑁 ≠ 1 ↔ 1 ≠ 𝑁) | |
11 | 1z 9208 | . . . . . . . 8 ⊢ 1 ∈ ℤ | |
12 | zltlen 9260 | . . . . . . . 8 ⊢ ((𝑁 ∈ ℤ ∧ 1 ∈ ℤ) → (𝑁 < 1 ↔ (𝑁 ≤ 1 ∧ 1 ≠ 𝑁))) | |
13 | 3, 11, 12 | sylancl 410 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 1 ↔ (𝑁 ≤ 1 ∧ 1 ≠ 𝑁))) |
14 | nn0lt10b 9262 | . . . . . . . . . 10 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 1 ↔ 𝑁 = 0)) | |
15 | 14 | biimpa 294 | . . . . . . . . 9 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 1) → 𝑁 = 0) |
16 | 15 | orcd 723 | . . . . . . . 8 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 1) → (𝑁 = 0 ∨ 𝑁 = 1)) |
17 | 16 | ex 114 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 1 → (𝑁 = 0 ∨ 𝑁 = 1))) |
18 | 13, 17 | sylbird 169 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 ≤ 1 ∧ 1 ≠ 𝑁) → (𝑁 = 0 ∨ 𝑁 = 1))) |
19 | 18 | expd 256 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → (𝑁 ≤ 1 → (1 ≠ 𝑁 → (𝑁 = 0 ∨ 𝑁 = 1)))) |
20 | 10, 19 | syl7bi 164 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 ≤ 1 → (𝑁 ≠ 1 → (𝑁 = 0 ∨ 𝑁 = 1)))) |
21 | 9, 20 | sylbid 149 | . . 3 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 2 → (𝑁 ≠ 1 → (𝑁 = 0 ∨ 𝑁 = 1)))) |
22 | 21 | imp 123 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 ≠ 1 → (𝑁 = 0 ∨ 𝑁 = 1))) |
23 | zdceq 9257 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 1 ∈ ℤ) → DECID 𝑁 = 1) | |
24 | 3, 11, 23 | sylancl 410 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → DECID 𝑁 = 1) |
25 | 24 | adantr 274 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → DECID 𝑁 = 1) |
26 | dcne 2345 | . . 3 ⊢ (DECID 𝑁 = 1 ↔ (𝑁 = 1 ∨ 𝑁 ≠ 1)) | |
27 | 25, 26 | sylib 121 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 = 1 ∨ 𝑁 ≠ 1)) |
28 | 2, 22, 27 | mpjaod 708 | 1 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 = 0 ∨ 𝑁 = 1)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 ↔ wb 104 ∨ wo 698 DECID wdc 824 = wceq 1342 ∈ wcel 2135 ≠ wne 2334 class class class wbr 3976 (class class class)co 5836 0cc0 7744 1c1 7745 < clt 7924 ≤ cle 7925 − cmin 8060 2c2 8899 ℕ0cn0 9105 ℤcz 9182 |
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 1434 ax-7 1435 ax-gen 1436 ax-ie1 1480 ax-ie2 1481 ax-8 1491 ax-10 1492 ax-11 1493 ax-i12 1494 ax-bndl 1496 ax-4 1497 ax-17 1513 ax-i9 1517 ax-ial 1521 ax-i5r 1522 ax-13 2137 ax-14 2138 ax-ext 2146 ax-sep 4094 ax-pow 4147 ax-pr 4181 ax-un 4405 ax-setind 4508 ax-cnex 7835 ax-resscn 7836 ax-1cn 7837 ax-1re 7838 ax-icn 7839 ax-addcl 7840 ax-addrcl 7841 ax-mulcl 7842 ax-mulrcl 7843 ax-addcom 7844 ax-mulcom 7845 ax-addass 7846 ax-mulass 7847 ax-distr 7848 ax-i2m1 7849 ax-0lt1 7850 ax-1rid 7851 ax-0id 7852 ax-rnegex 7853 ax-precex 7854 ax-cnre 7855 ax-pre-ltirr 7856 ax-pre-ltwlin 7857 ax-pre-lttrn 7858 ax-pre-apti 7859 ax-pre-ltadd 7860 ax-pre-mulgt0 7861 |
This theorem depends on definitions: df-bi 116 df-dc 825 df-3or 968 df-3an 969 df-tru 1345 df-fal 1348 df-nf 1448 df-sb 1750 df-eu 2016 df-mo 2017 df-clab 2151 df-cleq 2157 df-clel 2160 df-nfc 2295 df-ne 2335 df-nel 2430 df-ral 2447 df-rex 2448 df-reu 2449 df-rab 2451 df-v 2723 df-sbc 2947 df-dif 3113 df-un 3115 df-in 3117 df-ss 3124 df-pw 3555 df-sn 3576 df-pr 3577 df-op 3579 df-uni 3784 df-int 3819 df-br 3977 df-opab 4038 df-id 4265 df-xp 4604 df-rel 4605 df-cnv 4606 df-co 4607 df-dm 4608 df-iota 5147 df-fun 5184 df-fv 5190 df-riota 5792 df-ov 5839 df-oprab 5840 df-mpo 5841 df-pnf 7926 df-mnf 7927 df-xr 7928 df-ltxr 7929 df-le 7930 df-sub 8062 df-neg 8063 df-reap 8464 df-ap 8471 df-inn 8849 df-2 8907 df-n0 9106 df-z 9183 |
This theorem is referenced by: (None) |
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