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Mirrors > Home > MPE Home > Th. List > nn0oddm1d2 | Structured version Visualization version GIF version |
Description: A positive integer is odd iff its predecessor divided by 2 is a positive integer. (Contributed by AV, 28-Jun-2021.) (Proof shortened by AV, 10-Jul-2022.) |
Ref | Expression |
---|---|
nn0oddm1d2 | ⊢ (𝑁 ∈ ℕ0 → (¬ 2 ∥ 𝑁 ↔ ((𝑁 − 1) / 2) ∈ ℕ0)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nn0z 12605 | . . 3 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℤ) | |
2 | oddp1d2 16326 | . . 3 ⊢ (𝑁 ∈ ℤ → (¬ 2 ∥ 𝑁 ↔ ((𝑁 + 1) / 2) ∈ ℤ)) | |
3 | 1, 2 | syl 17 | . 2 ⊢ (𝑁 ∈ ℕ0 → (¬ 2 ∥ 𝑁 ↔ ((𝑁 + 1) / 2) ∈ ℤ)) |
4 | peano2nn0 12534 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ0 → (𝑁 + 1) ∈ ℕ0) | |
5 | 4 | nn0red 12555 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁 + 1) ∈ ℝ) |
6 | 2rp 13003 | . . . . . . . 8 ⊢ 2 ∈ ℝ+ | |
7 | 6 | a1i 11 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → 2 ∈ ℝ+) |
8 | nn0re 12503 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℝ) | |
9 | 1red 11237 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ0 → 1 ∈ ℝ) | |
10 | nn0ge0 12519 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ0 → 0 ≤ 𝑁) | |
11 | 0le1 11759 | . . . . . . . . 9 ⊢ 0 ≤ 1 | |
12 | 11 | a1i 11 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ0 → 0 ≤ 1) |
13 | 8, 9, 10, 12 | addge0d 11812 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → 0 ≤ (𝑁 + 1)) |
14 | 5, 7, 13 | divge0d 13080 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 0 ≤ ((𝑁 + 1) / 2)) |
15 | 14 | anim1ci 615 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ ((𝑁 + 1) / 2) ∈ ℤ) → (((𝑁 + 1) / 2) ∈ ℤ ∧ 0 ≤ ((𝑁 + 1) / 2))) |
16 | elnn0z 12593 | . . . . 5 ⊢ (((𝑁 + 1) / 2) ∈ ℕ0 ↔ (((𝑁 + 1) / 2) ∈ ℤ ∧ 0 ≤ ((𝑁 + 1) / 2))) | |
17 | 15, 16 | sylibr 233 | . . . 4 ⊢ ((𝑁 ∈ ℕ0 ∧ ((𝑁 + 1) / 2) ∈ ℤ) → ((𝑁 + 1) / 2) ∈ ℕ0) |
18 | 17 | ex 412 | . . 3 ⊢ (𝑁 ∈ ℕ0 → (((𝑁 + 1) / 2) ∈ ℤ → ((𝑁 + 1) / 2) ∈ ℕ0)) |
19 | nn0z 12605 | . . 3 ⊢ (((𝑁 + 1) / 2) ∈ ℕ0 → ((𝑁 + 1) / 2) ∈ ℤ) | |
20 | 18, 19 | impbid1 224 | . 2 ⊢ (𝑁 ∈ ℕ0 → (((𝑁 + 1) / 2) ∈ ℤ ↔ ((𝑁 + 1) / 2) ∈ ℕ0)) |
21 | nn0ob 16352 | . 2 ⊢ (𝑁 ∈ ℕ0 → (((𝑁 + 1) / 2) ∈ ℕ0 ↔ ((𝑁 − 1) / 2) ∈ ℕ0)) | |
22 | 3, 20, 21 | 3bitrd 305 | 1 ⊢ (𝑁 ∈ ℕ0 → (¬ 2 ∥ 𝑁 ↔ ((𝑁 − 1) / 2) ∈ ℕ0)) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 ∧ wa 395 ∈ wcel 2099 class class class wbr 5142 (class class class)co 7414 0cc0 11130 1c1 11131 + caddc 11133 ≤ cle 11271 − cmin 11466 / cdiv 11893 2c2 12289 ℕ0cn0 12494 ℤcz 12580 ℝ+crp 12998 ∥ cdvds 16222 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1790 ax-4 1804 ax-5 1906 ax-6 1964 ax-7 2004 ax-8 2101 ax-9 2109 ax-10 2130 ax-11 2147 ax-12 2164 ax-ext 2698 ax-sep 5293 ax-nul 5300 ax-pow 5359 ax-pr 5423 ax-un 7734 ax-cnex 11186 ax-resscn 11187 ax-1cn 11188 ax-icn 11189 ax-addcl 11190 ax-addrcl 11191 ax-mulcl 11192 ax-mulrcl 11193 ax-mulcom 11194 ax-addass 11195 ax-mulass 11196 ax-distr 11197 ax-i2m1 11198 ax-1ne0 11199 ax-1rid 11200 ax-rnegex 11201 ax-rrecex 11202 ax-cnre 11203 ax-pre-lttri 11204 ax-pre-lttrn 11205 ax-pre-ltadd 11206 ax-pre-mulgt0 11207 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 847 df-3or 1086 df-3an 1087 df-tru 1537 df-fal 1547 df-ex 1775 df-nf 1779 df-sb 2061 df-mo 2529 df-eu 2558 df-clab 2705 df-cleq 2719 df-clel 2805 df-nfc 2880 df-ne 2936 df-nel 3042 df-ral 3057 df-rex 3066 df-rmo 3371 df-reu 3372 df-rab 3428 df-v 3471 df-sbc 3775 df-csb 3890 df-dif 3947 df-un 3949 df-in 3951 df-ss 3961 df-pss 3963 df-nul 4319 df-if 4525 df-pw 4600 df-sn 4625 df-pr 4627 df-op 4631 df-uni 4904 df-iun 4993 df-br 5143 df-opab 5205 df-mpt 5226 df-tr 5260 df-id 5570 df-eprel 5576 df-po 5584 df-so 5585 df-fr 5627 df-we 5629 df-xp 5678 df-rel 5679 df-cnv 5680 df-co 5681 df-dm 5682 df-rn 5683 df-res 5684 df-ima 5685 df-pred 6299 df-ord 6366 df-on 6367 df-lim 6368 df-suc 6369 df-iota 6494 df-fun 6544 df-fn 6545 df-f 6546 df-f1 6547 df-fo 6548 df-f1o 6549 df-fv 6550 df-riota 7370 df-ov 7417 df-oprab 7418 df-mpo 7419 df-om 7865 df-2nd 7988 df-frecs 8280 df-wrecs 8311 df-recs 8385 df-rdg 8424 df-er 8718 df-en 8956 df-dom 8957 df-sdom 8958 df-pnf 11272 df-mnf 11273 df-xr 11274 df-ltxr 11275 df-le 11276 df-sub 11468 df-neg 11469 df-div 11894 df-nn 12235 df-2 12297 df-3 12298 df-4 12299 df-n0 12495 df-z 12581 df-uz 12845 df-rp 12999 df-dvds 16223 |
This theorem is referenced by: leibpilem1 26859 gausslemma2dlem6 27292 |
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