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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 9221 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℂ) | |
2 | 1cnd 8008 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 1 ∈ ℂ) | |
3 | 1, 2, 2 | subsub4d 8334 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 − 1) − 1) = (𝑁 − (1 + 1))) |
4 | 1p1e2 9071 | . . . . . 6 ⊢ (1 + 1) = 2 | |
5 | 4 | oveq2i 5911 | . . . . 5 ⊢ (𝑁 − (1 + 1)) = (𝑁 − 2) |
6 | 3, 5 | eqtr2di 2239 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 − 2) = ((𝑁 − 1) − 1)) |
7 | 6 | 3ad2ant1 1020 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 − 2) = ((𝑁 − 1) − 1)) |
8 | 3simpa 996 | . . . . . . 7 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0)) | |
9 | elnnne0 9225 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ ↔ (𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0)) | |
10 | 8, 9 | sylibr 134 | . . . . . 6 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → 𝑁 ∈ ℕ) |
11 | nnm1nn0 9252 | . . . . . 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 8313 | . . . . . . . . 9 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 − 1) = 0 ↔ 𝑁 = 1)) |
14 | 13 | biimpd 144 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 − 1) = 0 → 𝑁 = 1)) |
15 | 14 | necon3d 2404 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁 ≠ 1 → (𝑁 − 1) ≠ 0)) |
16 | 15 | imp 124 | . . . . . 6 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 1) → (𝑁 − 1) ≠ 0) |
17 | 16 | 3adant2 1018 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 − 1) ≠ 0) |
18 | elnnne0 9225 | . . . . 5 ⊢ ((𝑁 − 1) ∈ ℕ ↔ ((𝑁 − 1) ∈ ℕ0 ∧ (𝑁 − 1) ≠ 0)) | |
19 | 12, 17, 18 | sylanbrc 417 | . . . 4 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 − 1) ∈ ℕ) |
20 | nnm1nn0 9252 | . . . 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 2266 | . 2 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (𝑁 − 2) ∈ ℕ0) |
23 | 2nn0 9228 | . . . . 5 ⊢ 2 ∈ ℕ0 | |
24 | 23 | jctl 314 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (2 ∈ ℕ0 ∧ 𝑁 ∈ ℕ0)) |
25 | 24 | 3ad2ant1 1020 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → (2 ∈ ℕ0 ∧ 𝑁 ∈ ℕ0)) |
26 | nn0sub 9354 | . . 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 167 | 1 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑁 ≠ 0 ∧ 𝑁 ≠ 1) → 2 ≤ 𝑁) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 104 ↔ wb 105 ∧ w3a 980 = wceq 1364 ∈ wcel 2160 ≠ wne 2360 class class class wbr 4021 (class class class)co 5900 0cc0 7846 1c1 7847 + caddc 7849 ≤ cle 8028 − cmin 8163 ℕcn 8954 2c2 9005 ℕ0cn0 9211 |
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 4139 ax-pow 4195 ax-pr 4230 ax-un 4454 ax-setind 4557 ax-cnex 7937 ax-resscn 7938 ax-1cn 7939 ax-1re 7940 ax-icn 7941 ax-addcl 7942 ax-addrcl 7943 ax-mulcl 7944 ax-addcom 7946 ax-addass 7948 ax-distr 7950 ax-i2m1 7951 ax-0lt1 7952 ax-0id 7954 ax-rnegex 7955 ax-cnre 7957 ax-pre-ltirr 7958 ax-pre-ltwlin 7959 ax-pre-lttrn 7960 ax-pre-ltadd 7962 |
This theorem depends on definitions: df-bi 117 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-nul 3438 df-pw 3595 df-sn 3616 df-pr 3617 df-op 3619 df-uni 3828 df-int 3863 df-br 4022 df-opab 4083 df-id 4314 df-xp 4653 df-rel 4654 df-cnv 4655 df-co 4656 df-dm 4657 df-iota 5199 df-fun 5240 df-fv 5246 df-riota 5855 df-ov 5903 df-oprab 5904 df-mpo 5905 df-pnf 8029 df-mnf 8030 df-xr 8031 df-ltxr 8032 df-le 8033 df-sub 8165 df-neg 8166 df-inn 8955 df-2 9013 df-n0 9212 df-z 9289 |
This theorem is referenced by: nn0n0n1ge2b 9367 |
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