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Mirrors > Home > ILE Home > Th. List > nn0enne | GIF version |
Description: A positive integer is an even nonnegative integer iff it is an even positive integer. (Contributed by AV, 30-May-2020.) |
Ref | Expression |
---|---|
nn0enne | ⊢ (𝑁 ∈ ℕ → ((𝑁 / 2) ∈ ℕ0 ↔ (𝑁 / 2) ∈ ℕ)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elnn0 8972 | . . . 4 ⊢ ((𝑁 / 2) ∈ ℕ0 ↔ ((𝑁 / 2) ∈ ℕ ∨ (𝑁 / 2) = 0)) | |
2 | nncn 8721 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ → 𝑁 ∈ ℂ) | |
3 | 2cnd 8786 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ → 2 ∈ ℂ) | |
4 | 2ap0 8806 | . . . . . . . . 9 ⊢ 2 # 0 | |
5 | 4 | a1i 9 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ → 2 # 0) |
6 | 2, 3, 5 | diveqap0ad 8553 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ → ((𝑁 / 2) = 0 ↔ 𝑁 = 0)) |
7 | eleq1 2200 | . . . . . . . . 9 ⊢ (𝑁 = 0 → (𝑁 ∈ ℕ ↔ 0 ∈ ℕ)) | |
8 | 0nnn 8740 | . . . . . . . . . 10 ⊢ ¬ 0 ∈ ℕ | |
9 | 8 | pm2.21i 635 | . . . . . . . . 9 ⊢ (0 ∈ ℕ → (𝑁 / 2) ∈ ℕ) |
10 | 7, 9 | syl6bi 162 | . . . . . . . 8 ⊢ (𝑁 = 0 → (𝑁 ∈ ℕ → (𝑁 / 2) ∈ ℕ)) |
11 | 10 | com12 30 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ → (𝑁 = 0 → (𝑁 / 2) ∈ ℕ)) |
12 | 6, 11 | sylbid 149 | . . . . . 6 ⊢ (𝑁 ∈ ℕ → ((𝑁 / 2) = 0 → (𝑁 / 2) ∈ ℕ)) |
13 | 12 | com12 30 | . . . . 5 ⊢ ((𝑁 / 2) = 0 → (𝑁 ∈ ℕ → (𝑁 / 2) ∈ ℕ)) |
14 | 13 | jao1i 785 | . . . 4 ⊢ (((𝑁 / 2) ∈ ℕ ∨ (𝑁 / 2) = 0) → (𝑁 ∈ ℕ → (𝑁 / 2) ∈ ℕ)) |
15 | 1, 14 | sylbi 120 | . . 3 ⊢ ((𝑁 / 2) ∈ ℕ0 → (𝑁 ∈ ℕ → (𝑁 / 2) ∈ ℕ)) |
16 | 15 | com12 30 | . 2 ⊢ (𝑁 ∈ ℕ → ((𝑁 / 2) ∈ ℕ0 → (𝑁 / 2) ∈ ℕ)) |
17 | nnnn0 8977 | . 2 ⊢ ((𝑁 / 2) ∈ ℕ → (𝑁 / 2) ∈ ℕ0) | |
18 | 16, 17 | impbid1 141 | 1 ⊢ (𝑁 ∈ ℕ → ((𝑁 / 2) ∈ ℕ0 ↔ (𝑁 / 2) ∈ ℕ)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ↔ wb 104 ∨ wo 697 = wceq 1331 ∈ wcel 1480 class class class wbr 3924 (class class class)co 5767 0cc0 7613 # cap 8336 / cdiv 8425 ℕcn 8713 2c2 8764 ℕ0cn0 8970 |
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 603 ax-in2 604 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-bndl 1486 ax-4 1487 ax-13 1491 ax-14 1492 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2119 ax-sep 4041 ax-pow 4093 ax-pr 4126 ax-un 4350 ax-setind 4447 ax-cnex 7704 ax-resscn 7705 ax-1cn 7706 ax-1re 7707 ax-icn 7708 ax-addcl 7709 ax-addrcl 7710 ax-mulcl 7711 ax-mulrcl 7712 ax-addcom 7713 ax-mulcom 7714 ax-addass 7715 ax-mulass 7716 ax-distr 7717 ax-i2m1 7718 ax-0lt1 7719 ax-1rid 7720 ax-0id 7721 ax-rnegex 7722 ax-precex 7723 ax-cnre 7724 ax-pre-ltirr 7725 ax-pre-ltwlin 7726 ax-pre-lttrn 7727 ax-pre-apti 7728 ax-pre-ltadd 7729 ax-pre-mulgt0 7730 ax-pre-mulext 7731 |
This theorem depends on definitions: df-bi 116 df-3an 964 df-tru 1334 df-fal 1337 df-nf 1437 df-sb 1736 df-eu 2000 df-mo 2001 df-clab 2124 df-cleq 2130 df-clel 2133 df-nfc 2268 df-ne 2307 df-nel 2402 df-ral 2419 df-rex 2420 df-reu 2421 df-rmo 2422 df-rab 2423 df-v 2683 df-sbc 2905 df-dif 3068 df-un 3070 df-in 3072 df-ss 3079 df-pw 3507 df-sn 3528 df-pr 3529 df-op 3531 df-uni 3732 df-int 3767 df-br 3925 df-opab 3985 df-id 4210 df-po 4213 df-iso 4214 df-xp 4540 df-rel 4541 df-cnv 4542 df-co 4543 df-dm 4544 df-iota 5083 df-fun 5120 df-fv 5126 df-riota 5723 df-ov 5770 df-oprab 5771 df-mpo 5772 df-pnf 7795 df-mnf 7796 df-xr 7797 df-ltxr 7798 df-le 7799 df-sub 7928 df-neg 7929 df-reap 8330 df-ap 8337 df-div 8426 df-inn 8714 df-2 8772 df-n0 8971 |
This theorem is referenced by: nnehalf 11590 |
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