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Mirrors > Home > ILE Home > Th. List > oddm1even | GIF version |
Description: An integer is odd iff its predecessor is even. (Contributed by Mario Carneiro, 5-Sep-2016.) |
Ref | Expression |
---|---|
oddm1even | ⊢ (𝑁 ∈ ℤ → (¬ 2 ∥ 𝑁 ↔ 2 ∥ (𝑁 − 1))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpl 108 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑁 ∈ ℤ) | |
2 | 1 | zcnd 8923 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑁 ∈ ℂ) |
3 | 1cnd 7558 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 1 ∈ ℂ) | |
4 | 2cnd 8549 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 2 ∈ ℂ) | |
5 | simpr 109 | . . . . . . 7 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑛 ∈ ℤ) | |
6 | 5 | zcnd 8923 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑛 ∈ ℂ) |
7 | 4, 6 | mulcld 7562 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → (2 · 𝑛) ∈ ℂ) |
8 | 2, 3, 7 | subadd2d 7866 | . . . 4 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → ((𝑁 − 1) = (2 · 𝑛) ↔ ((2 · 𝑛) + 1) = 𝑁)) |
9 | eqcom 2091 | . . . . 5 ⊢ ((𝑁 − 1) = (2 · 𝑛) ↔ (2 · 𝑛) = (𝑁 − 1)) | |
10 | 4, 6 | mulcomd 7563 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → (2 · 𝑛) = (𝑛 · 2)) |
11 | 10 | eqeq1d 2097 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → ((2 · 𝑛) = (𝑁 − 1) ↔ (𝑛 · 2) = (𝑁 − 1))) |
12 | 9, 11 | syl5bb 191 | . . . 4 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → ((𝑁 − 1) = (2 · 𝑛) ↔ (𝑛 · 2) = (𝑁 − 1))) |
13 | 8, 12 | bitr3d 189 | . . 3 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → (((2 · 𝑛) + 1) = 𝑁 ↔ (𝑛 · 2) = (𝑁 − 1))) |
14 | 13 | rexbidva 2378 | . 2 ⊢ (𝑁 ∈ ℤ → (∃𝑛 ∈ ℤ ((2 · 𝑛) + 1) = 𝑁 ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = (𝑁 − 1))) |
15 | odd2np1 11205 | . 2 ⊢ (𝑁 ∈ ℤ → (¬ 2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ ((2 · 𝑛) + 1) = 𝑁)) | |
16 | 2z 8832 | . . 3 ⊢ 2 ∈ ℤ | |
17 | peano2zm 8842 | . . 3 ⊢ (𝑁 ∈ ℤ → (𝑁 − 1) ∈ ℤ) | |
18 | divides 11130 | . . 3 ⊢ ((2 ∈ ℤ ∧ (𝑁 − 1) ∈ ℤ) → (2 ∥ (𝑁 − 1) ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = (𝑁 − 1))) | |
19 | 16, 17, 18 | sylancr 406 | . 2 ⊢ (𝑁 ∈ ℤ → (2 ∥ (𝑁 − 1) ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = (𝑁 − 1))) |
20 | 14, 15, 19 | 3bitr4d 219 | 1 ⊢ (𝑁 ∈ ℤ → (¬ 2 ∥ 𝑁 ↔ 2 ∥ (𝑁 − 1))) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 103 ↔ wb 104 = wceq 1290 ∈ wcel 1439 ∃wrex 2361 class class class wbr 3851 (class class class)co 5666 1c1 7405 + caddc 7407 · cmul 7409 − cmin 7707 2c2 8527 ℤcz 8804 ∥ cdvds 11128 |
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 580 ax-in2 581 ax-io 666 ax-5 1382 ax-7 1383 ax-gen 1384 ax-ie1 1428 ax-ie2 1429 ax-8 1441 ax-10 1442 ax-11 1443 ax-i12 1444 ax-bndl 1445 ax-4 1446 ax-13 1450 ax-14 1451 ax-17 1465 ax-i9 1469 ax-ial 1473 ax-i5r 1474 ax-ext 2071 ax-sep 3963 ax-pow 4015 ax-pr 4045 ax-un 4269 ax-setind 4366 ax-cnex 7490 ax-resscn 7491 ax-1cn 7492 ax-1re 7493 ax-icn 7494 ax-addcl 7495 ax-addrcl 7496 ax-mulcl 7497 ax-mulrcl 7498 ax-addcom 7499 ax-mulcom 7500 ax-addass 7501 ax-mulass 7502 ax-distr 7503 ax-i2m1 7504 ax-0lt1 7505 ax-1rid 7506 ax-0id 7507 ax-rnegex 7508 ax-precex 7509 ax-cnre 7510 ax-pre-ltirr 7511 ax-pre-ltwlin 7512 ax-pre-lttrn 7513 ax-pre-apti 7514 ax-pre-ltadd 7515 ax-pre-mulgt0 7516 ax-pre-mulext 7517 |
This theorem depends on definitions: df-bi 116 df-3or 926 df-3an 927 df-tru 1293 df-fal 1296 df-xor 1313 df-nf 1396 df-sb 1694 df-eu 1952 df-mo 1953 df-clab 2076 df-cleq 2082 df-clel 2085 df-nfc 2218 df-ne 2257 df-nel 2352 df-ral 2365 df-rex 2366 df-reu 2367 df-rmo 2368 df-rab 2369 df-v 2622 df-sbc 2842 df-dif 3002 df-un 3004 df-in 3006 df-ss 3013 df-pw 3435 df-sn 3456 df-pr 3457 df-op 3459 df-uni 3660 df-int 3695 df-br 3852 df-opab 3906 df-id 4129 df-po 4132 df-iso 4133 df-xp 4457 df-rel 4458 df-cnv 4459 df-co 4460 df-dm 4461 df-iota 4993 df-fun 5030 df-fv 5036 df-riota 5622 df-ov 5669 df-oprab 5670 df-mpt2 5671 df-pnf 7578 df-mnf 7579 df-xr 7580 df-ltxr 7581 df-le 7582 df-sub 7709 df-neg 7710 df-reap 8106 df-ap 8113 df-div 8194 df-inn 8477 df-2 8535 df-n0 8728 df-z 8805 df-dvds 11129 |
This theorem is referenced by: oddp1even 11208 n2dvds3 11247 oddennn 11537 |
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