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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 109 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑁 ∈ ℤ) | |
2 | 1 | zcnd 9394 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑁 ∈ ℂ) |
3 | 1cnd 7991 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 1 ∈ ℂ) | |
4 | 2cnd 9010 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 2 ∈ ℂ) | |
5 | simpr 110 | . . . . . . 7 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑛 ∈ ℤ) | |
6 | 5 | zcnd 9394 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑛 ∈ ℂ) |
7 | 4, 6 | mulcld 7996 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → (2 · 𝑛) ∈ ℂ) |
8 | 2, 3, 7 | subadd2d 8305 | . . . 4 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → ((𝑁 − 1) = (2 · 𝑛) ↔ ((2 · 𝑛) + 1) = 𝑁)) |
9 | eqcom 2191 | . . . . 5 ⊢ ((𝑁 − 1) = (2 · 𝑛) ↔ (2 · 𝑛) = (𝑁 − 1)) | |
10 | 4, 6 | mulcomd 7997 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → (2 · 𝑛) = (𝑛 · 2)) |
11 | 10 | eqeq1d 2198 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → ((2 · 𝑛) = (𝑁 − 1) ↔ (𝑛 · 2) = (𝑁 − 1))) |
12 | 9, 11 | bitrid 192 | . . . 4 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → ((𝑁 − 1) = (2 · 𝑛) ↔ (𝑛 · 2) = (𝑁 − 1))) |
13 | 8, 12 | bitr3d 190 | . . 3 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → (((2 · 𝑛) + 1) = 𝑁 ↔ (𝑛 · 2) = (𝑁 − 1))) |
14 | 13 | rexbidva 2487 | . 2 ⊢ (𝑁 ∈ ℤ → (∃𝑛 ∈ ℤ ((2 · 𝑛) + 1) = 𝑁 ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = (𝑁 − 1))) |
15 | odd2np1 11896 | . 2 ⊢ (𝑁 ∈ ℤ → (¬ 2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ ((2 · 𝑛) + 1) = 𝑁)) | |
16 | 2z 9299 | . . 3 ⊢ 2 ∈ ℤ | |
17 | peano2zm 9309 | . . 3 ⊢ (𝑁 ∈ ℤ → (𝑁 − 1) ∈ ℤ) | |
18 | divides 11814 | . . 3 ⊢ ((2 ∈ ℤ ∧ (𝑁 − 1) ∈ ℤ) → (2 ∥ (𝑁 − 1) ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = (𝑁 − 1))) | |
19 | 16, 17, 18 | sylancr 414 | . 2 ⊢ (𝑁 ∈ ℤ → (2 ∥ (𝑁 − 1) ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = (𝑁 − 1))) |
20 | 14, 15, 19 | 3bitr4d 220 | 1 ⊢ (𝑁 ∈ ℤ → (¬ 2 ∥ 𝑁 ↔ 2 ∥ (𝑁 − 1))) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 104 ↔ wb 105 = wceq 1364 ∈ wcel 2160 ∃wrex 2469 class class class wbr 4018 (class class class)co 5891 1c1 7830 + caddc 7832 · cmul 7834 − cmin 8146 2c2 8988 ℤcz 9271 ∥ cdvds 11812 |
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 4136 ax-pow 4189 ax-pr 4224 ax-un 4448 ax-setind 4551 ax-cnex 7920 ax-resscn 7921 ax-1cn 7922 ax-1re 7923 ax-icn 7924 ax-addcl 7925 ax-addrcl 7926 ax-mulcl 7927 ax-mulrcl 7928 ax-addcom 7929 ax-mulcom 7930 ax-addass 7931 ax-mulass 7932 ax-distr 7933 ax-i2m1 7934 ax-0lt1 7935 ax-1rid 7936 ax-0id 7937 ax-rnegex 7938 ax-precex 7939 ax-cnre 7940 ax-pre-ltirr 7941 ax-pre-ltwlin 7942 ax-pre-lttrn 7943 ax-pre-apti 7944 ax-pre-ltadd 7945 ax-pre-mulgt0 7946 ax-pre-mulext 7947 |
This theorem depends on definitions: df-bi 117 df-3or 981 df-3an 982 df-tru 1367 df-fal 1370 df-xor 1387 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-rmo 2476 df-rab 2477 df-v 2754 df-sbc 2978 df-dif 3146 df-un 3148 df-in 3150 df-ss 3157 df-pw 3592 df-sn 3613 df-pr 3614 df-op 3616 df-uni 3825 df-int 3860 df-br 4019 df-opab 4080 df-id 4308 df-po 4311 df-iso 4312 df-xp 4647 df-rel 4648 df-cnv 4649 df-co 4650 df-dm 4651 df-iota 5193 df-fun 5233 df-fv 5239 df-riota 5847 df-ov 5894 df-oprab 5895 df-mpo 5896 df-pnf 8012 df-mnf 8013 df-xr 8014 df-ltxr 8015 df-le 8016 df-sub 8148 df-neg 8149 df-reap 8550 df-ap 8557 df-div 8648 df-inn 8938 df-2 8996 df-n0 9195 df-z 9272 df-dvds 11813 |
This theorem is referenced by: oddp1even 11899 n2dvds3 11938 oddennn 12411 |
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