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Mirrors > Home > ILE Home > Th. List > nn0n0n1ge2 | GIF version |
Description: A nonnegative integer which is neither 0 nor 1 is greater than or equal to 2. (Contributed by Alexander van der Vekens, 6-Dec-2017.) |
Ref | Expression |
---|---|
nn0n0n1ge2 | ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → 2 ≤ 𝑁) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nn0cn 9145 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℂ) | |
2 | 1cnd 7936 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 1 ∈ ℂ) | |
3 | 1, 2, 2 | subsub4d 8261 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 − 1) − 1) = (𝑁 − (1 + 1))) |
4 | 1p1e2 8995 | . . . . . 6 ⊢ (1 + 1) = 2 | |
5 | 4 | oveq2i 5864 | . . . . 5 ⊢ (𝑁 − (1 + 1)) = (𝑁 − 2) |
6 | 3, 5 | eqtr2di 2220 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 − 2) = ((𝑁 − 1) − 1)) |
7 | 6 | 3ad2ant1 1013 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 − 2) = ((𝑁 − 1) − 1)) |
8 | 3simpa 989 | . . . . . . 7 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0)) | |
9 | elnnne0 9149 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ ↔ (𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0)) | |
10 | 8, 9 | sylibr 133 | . . . . . 6 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → 𝑁 ∈ ℕ) |
11 | nnm1nn0 9176 | . . . . . 6 ⊢ (𝑁 ∈ ℕ → (𝑁 − 1) ∈ ℕ0) | |
12 | 10, 11 | syl 14 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 − 1) ∈ ℕ0) |
13 | 1, 2 | subeq0ad 8240 | . . . . . . . . 9 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 − 1) = 0 ↔ 𝑁 = 1)) |
14 | 13 | biimpd 143 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 − 1) = 0 → 𝑁 = 1)) |
15 | 14 | necon3d 2384 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁 ≠ 1 → (𝑁 − 1) ≠ 0)) |
16 | 15 | imp 123 | . . . . . 6 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 1) → (𝑁 − 1) ≠ 0) |
17 | 16 | 3adant2 1011 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 − 1) ≠ 0) |
18 | elnnne0 9149 | . . . . 5 ⊢ ((𝑁 − 1) ∈ ℕ ↔ ((𝑁 − 1) ∈ ℕ0 ∧ (𝑁 − 1) ≠ 0)) | |
19 | 12, 17, 18 | sylanbrc 415 | . . . 4 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 − 1) ∈ ℕ) |
20 | nnm1nn0 9176 | . . . 4 ⊢ ((𝑁 − 1) ∈ ℕ → ((𝑁 − 1) − 1) ∈ ℕ0) | |
21 | 19, 20 | syl 14 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → ((𝑁 − 1) − 1) ∈ ℕ0) |
22 | 7, 21 | eqeltrd 2247 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 − 2) ∈ ℕ0) |
23 | 2nn0 9152 | . . . . 5 ⊢ 2 ∈ ℕ0 | |
24 | 23 | jctl 312 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (2 ∈ ℕ0 ∧ 𝑁 ∈ ℕ0)) |
25 | 24 | 3ad2ant1 1013 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (2 ∈ ℕ0 ∧ 𝑁 ∈ ℕ0)) |
26 | nn0sub 9278 | . . 3 ⊢ ((2 ∈ ℕ0 ∧ 𝑁 ∈ ℕ0) → (2 ≤ 𝑁 ↔ (𝑁 − 2) ∈ ℕ0)) | |
27 | 25, 26 | syl 14 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (2 ≤ 𝑁 ↔ (𝑁 − 2) ∈ ℕ0)) |
28 | 22, 27 | mpbird 166 | 1 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → 2 ≤ 𝑁) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 ↔ wb 104 ∧ w3a 973 = wceq 1348 ∈ wcel 2141 ≠ wne 2340 class class class wbr 3989 (class class class)co 5853 0cc0 7774 1c1 7775 + caddc 7777 ≤ cle 7955 − cmin 8090 ℕcn 8878 2c2 8929 ℕ0cn0 9135 |
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 609 ax-in2 610 ax-io 704 ax-5 1440 ax-7 1441 ax-gen 1442 ax-ie1 1486 ax-ie2 1487 ax-8 1497 ax-10 1498 ax-11 1499 ax-i12 1500 ax-bndl 1502 ax-4 1503 ax-17 1519 ax-i9 1523 ax-ial 1527 ax-i5r 1528 ax-13 2143 ax-14 2144 ax-ext 2152 ax-sep 4107 ax-pow 4160 ax-pr 4194 ax-un 4418 ax-setind 4521 ax-cnex 7865 ax-resscn 7866 ax-1cn 7867 ax-1re 7868 ax-icn 7869 ax-addcl 7870 ax-addrcl 7871 ax-mulcl 7872 ax-addcom 7874 ax-addass 7876 ax-distr 7878 ax-i2m1 7879 ax-0lt1 7880 ax-0id 7882 ax-rnegex 7883 ax-cnre 7885 ax-pre-ltirr 7886 ax-pre-ltwlin 7887 ax-pre-lttrn 7888 ax-pre-ltadd 7890 |
This theorem depends on definitions: df-bi 116 df-3or 974 df-3an 975 df-tru 1351 df-fal 1354 df-nf 1454 df-sb 1756 df-eu 2022 df-mo 2023 df-clab 2157 df-cleq 2163 df-clel 2166 df-nfc 2301 df-ne 2341 df-nel 2436 df-ral 2453 df-rex 2454 df-reu 2455 df-rab 2457 df-v 2732 df-sbc 2956 df-dif 3123 df-un 3125 df-in 3127 df-ss 3134 df-nul 3415 df-pw 3568 df-sn 3589 df-pr 3590 df-op 3592 df-uni 3797 df-int 3832 df-br 3990 df-opab 4051 df-id 4278 df-xp 4617 df-rel 4618 df-cnv 4619 df-co 4620 df-dm 4621 df-iota 5160 df-fun 5200 df-fv 5206 df-riota 5809 df-ov 5856 df-oprab 5857 df-mpo 5858 df-pnf 7956 df-mnf 7957 df-xr 7958 df-ltxr 7959 df-le 7960 df-sub 8092 df-neg 8093 df-inn 8879 df-2 8937 df-n0 9136 df-z 9213 |
This theorem is referenced by: nn0n0n1ge2b 9291 |
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