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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 712 | . . 3 ⊢ (𝑁 = 1 → (𝑁 = 0 ∨ 𝑁 = 1)) | |
2 | 1 | a1i 9 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 = 1 → (𝑁 = 0 ∨ 𝑁 = 1))) |
3 | nn0z 9303 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℤ) | |
4 | 2z 9311 | . . . . . 6 ⊢ 2 ∈ ℤ | |
5 | zltlem1 9340 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 2 ∈ ℤ) → (𝑁 < 2 ↔ 𝑁 ≤ (2 − 1))) | |
6 | 3, 4, 5 | sylancl 413 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 2 ↔ 𝑁 ≤ (2 − 1))) |
7 | 2m1e1 9067 | . . . . . 6 ⊢ (2 − 1) = 1 | |
8 | 7 | breq2i 4026 | . . . . 5 ⊢ (𝑁 ≤ (2 − 1) ↔ 𝑁 ≤ 1) |
9 | 6, 8 | bitrdi 196 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 2 ↔ 𝑁 ≤ 1)) |
10 | necom 2444 | . . . . 5 ⊢ (𝑁 ≠ 1 ↔ 1 ≠ 𝑁) | |
11 | 1z 9309 | . . . . . . . 8 ⊢ 1 ∈ ℤ | |
12 | zltlen 9361 | . . . . . . . 8 ⊢ ((𝑁 ∈ ℤ ∧ 1 ∈ ℤ) → (𝑁 < 1 ↔ (𝑁 ≤ 1 ∧ 1 ≠ 𝑁))) | |
13 | 3, 11, 12 | sylancl 413 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 1 ↔ (𝑁 ≤ 1 ∧ 1 ≠ 𝑁))) |
14 | nn0lt10b 9363 | . . . . . . . . . 10 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 1 ↔ 𝑁 = 0)) | |
15 | 14 | biimpa 296 | . . . . . . . . 9 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 1) → 𝑁 = 0) |
16 | 15 | orcd 734 | . . . . . . . 8 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 1) → (𝑁 = 0 ∨ 𝑁 = 1)) |
17 | 16 | ex 115 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 1 → (𝑁 = 0 ∨ 𝑁 = 1))) |
18 | 13, 17 | sylbird 170 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 ≤ 1 ∧ 1 ≠ 𝑁) → (𝑁 = 0 ∨ 𝑁 = 1))) |
19 | 18 | expd 258 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → (𝑁 ≤ 1 → (1 ≠ 𝑁 → (𝑁 = 0 ∨ 𝑁 = 1)))) |
20 | 10, 19 | syl7bi 165 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 ≤ 1 → (𝑁 ≠ 1 → (𝑁 = 0 ∨ 𝑁 = 1)))) |
21 | 9, 20 | sylbid 150 | . . 3 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 2 → (𝑁 ≠ 1 → (𝑁 = 0 ∨ 𝑁 = 1)))) |
22 | 21 | imp 124 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 ≠ 1 → (𝑁 = 0 ∨ 𝑁 = 1))) |
23 | zdceq 9358 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 1 ∈ ℤ) → DECID 𝑁 = 1) | |
24 | 3, 11, 23 | sylancl 413 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → DECID 𝑁 = 1) |
25 | 24 | adantr 276 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → DECID 𝑁 = 1) |
26 | dcne 2371 | . . 3 ⊢ (DECID 𝑁 = 1 ↔ (𝑁 = 1 ∨ 𝑁 ≠ 1)) | |
27 | 25, 26 | sylib 122 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 = 1 ∨ 𝑁 ≠ 1)) |
28 | 2, 22, 27 | mpjaod 719 | 1 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 = 0 ∨ 𝑁 = 1)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 104 ↔ wb 105 ∨ wo 709 DECID wdc 835 = wceq 1364 ∈ wcel 2160 ≠ wne 2360 class class class wbr 4018 (class class class)co 5896 0cc0 7841 1c1 7842 < clt 8022 ≤ cle 8023 − cmin 8158 2c2 9000 ℕ0cn0 9206 ℤcz 9283 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 615 ax-in2 616 ax-io 710 ax-5 1458 ax-7 1459 ax-gen 1460 ax-ie1 1504 ax-ie2 1505 ax-8 1515 ax-10 1516 ax-11 1517 ax-i12 1518 ax-bndl 1520 ax-4 1521 ax-17 1537 ax-i9 1541 ax-ial 1545 ax-i5r 1546 ax-13 2162 ax-14 2163 ax-ext 2171 ax-sep 4136 ax-pow 4192 ax-pr 4227 ax-un 4451 ax-setind 4554 ax-cnex 7932 ax-resscn 7933 ax-1cn 7934 ax-1re 7935 ax-icn 7936 ax-addcl 7937 ax-addrcl 7938 ax-mulcl 7939 ax-mulrcl 7940 ax-addcom 7941 ax-mulcom 7942 ax-addass 7943 ax-mulass 7944 ax-distr 7945 ax-i2m1 7946 ax-0lt1 7947 ax-1rid 7948 ax-0id 7949 ax-rnegex 7950 ax-precex 7951 ax-cnre 7952 ax-pre-ltirr 7953 ax-pre-ltwlin 7954 ax-pre-lttrn 7955 ax-pre-apti 7956 ax-pre-ltadd 7957 ax-pre-mulgt0 7958 |
This theorem depends on definitions: df-bi 117 df-dc 836 df-3or 981 df-3an 982 df-tru 1367 df-fal 1370 df-nf 1472 df-sb 1774 df-eu 2041 df-mo 2042 df-clab 2176 df-cleq 2182 df-clel 2185 df-nfc 2321 df-ne 2361 df-nel 2456 df-ral 2473 df-rex 2474 df-reu 2475 df-rab 2477 df-v 2754 df-sbc 2978 df-dif 3146 df-un 3148 df-in 3150 df-ss 3157 df-pw 3592 df-sn 3613 df-pr 3614 df-op 3616 df-uni 3825 df-int 3860 df-br 4019 df-opab 4080 df-id 4311 df-xp 4650 df-rel 4651 df-cnv 4652 df-co 4653 df-dm 4654 df-iota 5196 df-fun 5237 df-fv 5243 df-riota 5852 df-ov 5899 df-oprab 5900 df-mpo 5901 df-pnf 8024 df-mnf 8025 df-xr 8026 df-ltxr 8027 df-le 8028 df-sub 8160 df-neg 8161 df-reap 8562 df-ap 8569 df-inn 8950 df-2 9008 df-n0 9207 df-z 9284 |
This theorem is referenced by: (None) |
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