![]() |
Intuitionistic Logic Explorer |
< Previous
Next >
Nearby theorems |
|
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 670 | . . 3 ⊢ (𝑁 = 1 → (𝑁 = 0 ∨ 𝑁 = 1)) | |
2 | 1 | a1i 9 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 = 1 → (𝑁 = 0 ∨ 𝑁 = 1))) |
3 | nn0z 8868 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℤ) | |
4 | 2z 8876 | . . . . . 6 ⊢ 2 ∈ ℤ | |
5 | zltlem1 8905 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 2 ∈ ℤ) → (𝑁 < 2 ↔ 𝑁 ≤ (2 − 1))) | |
6 | 3, 4, 5 | sylancl 405 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 2 ↔ 𝑁 ≤ (2 − 1))) |
7 | 2m1e1 8638 | . . . . . 6 ⊢ (2 − 1) = 1 | |
8 | 7 | breq2i 3875 | . . . . 5 ⊢ (𝑁 ≤ (2 − 1) ↔ 𝑁 ≤ 1) |
9 | 6, 8 | syl6bb 195 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 2 ↔ 𝑁 ≤ 1)) |
10 | necom 2346 | . . . . 5 ⊢ (𝑁 ≠ 1 ↔ 1 ≠ 𝑁) | |
11 | 1z 8874 | . . . . . . . 8 ⊢ 1 ∈ ℤ | |
12 | zltlen 8923 | . . . . . . . 8 ⊢ ((𝑁 ∈ ℤ ∧ 1 ∈ ℤ) → (𝑁 < 1 ↔ (𝑁 ≤ 1 ∧ 1 ≠ 𝑁))) | |
13 | 3, 11, 12 | sylancl 405 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 1 ↔ (𝑁 ≤ 1 ∧ 1 ≠ 𝑁))) |
14 | nn0lt10b 8925 | . . . . . . . . . 10 ⊢ (𝑁 ∈ ℕ0 → (𝑁 < 1 ↔ 𝑁 = 0)) | |
15 | 14 | biimpa 291 | . . . . . . . . 9 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 1) → 𝑁 = 0) |
16 | 15 | orcd 690 | . . . . . . . 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 255 | . . . . 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 8920 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 1 ∈ ℤ) → DECID 𝑁 = 1) | |
24 | 3, 11, 23 | sylancl 405 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → DECID 𝑁 = 1) |
25 | 24 | adantr 271 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → DECID 𝑁 = 1) |
26 | dcne 2273 | . . 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 676 | 1 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 < 2) → (𝑁 = 0 ∨ 𝑁 = 1)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 ↔ wb 104 ∨ wo 667 DECID wdc 783 = wceq 1296 ∈ wcel 1445 ≠ wne 2262 class class class wbr 3867 (class class class)co 5690 0cc0 7447 1c1 7448 < clt 7619 ≤ cle 7620 − cmin 7750 2c2 8571 ℕ0cn0 8771 ℤcz 8848 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 582 ax-in2 583 ax-io 668 ax-5 1388 ax-7 1389 ax-gen 1390 ax-ie1 1434 ax-ie2 1435 ax-8 1447 ax-10 1448 ax-11 1449 ax-i12 1450 ax-bndl 1451 ax-4 1452 ax-13 1456 ax-14 1457 ax-17 1471 ax-i9 1475 ax-ial 1479 ax-i5r 1480 ax-ext 2077 ax-sep 3978 ax-pow 4030 ax-pr 4060 ax-un 4284 ax-setind 4381 ax-cnex 7533 ax-resscn 7534 ax-1cn 7535 ax-1re 7536 ax-icn 7537 ax-addcl 7538 ax-addrcl 7539 ax-mulcl 7540 ax-mulrcl 7541 ax-addcom 7542 ax-mulcom 7543 ax-addass 7544 ax-mulass 7545 ax-distr 7546 ax-i2m1 7547 ax-0lt1 7548 ax-1rid 7549 ax-0id 7550 ax-rnegex 7551 ax-precex 7552 ax-cnre 7553 ax-pre-ltirr 7554 ax-pre-ltwlin 7555 ax-pre-lttrn 7556 ax-pre-apti 7557 ax-pre-ltadd 7558 ax-pre-mulgt0 7559 |
This theorem depends on definitions: df-bi 116 df-dc 784 df-3or 928 df-3an 929 df-tru 1299 df-fal 1302 df-nf 1402 df-sb 1700 df-eu 1958 df-mo 1959 df-clab 2082 df-cleq 2088 df-clel 2091 df-nfc 2224 df-ne 2263 df-nel 2358 df-ral 2375 df-rex 2376 df-reu 2377 df-rab 2379 df-v 2635 df-sbc 2855 df-dif 3015 df-un 3017 df-in 3019 df-ss 3026 df-pw 3451 df-sn 3472 df-pr 3473 df-op 3475 df-uni 3676 df-int 3711 df-br 3868 df-opab 3922 df-id 4144 df-xp 4473 df-rel 4474 df-cnv 4475 df-co 4476 df-dm 4477 df-iota 5014 df-fun 5051 df-fv 5057 df-riota 5646 df-ov 5693 df-oprab 5694 df-mpt2 5695 df-pnf 7621 df-mnf 7622 df-xr 7623 df-ltxr 7624 df-le 7625 df-sub 7752 df-neg 7753 df-reap 8149 df-ap 8156 df-inn 8521 df-2 8579 df-n0 8772 df-z 8849 |
This theorem is referenced by: (None) |
Copyright terms: Public domain | W3C validator |