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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 9292 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑁 ∈ ℂ) |
3 | 1cnd 7896 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 1 ∈ ℂ) | |
4 | 2cnd 8911 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 2 ∈ ℂ) | |
5 | simpr 109 | . . . . . . 7 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑛 ∈ ℤ) | |
6 | 5 | zcnd 9292 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → 𝑛 ∈ ℂ) |
7 | 4, 6 | mulcld 7900 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → (2 · 𝑛) ∈ ℂ) |
8 | 2, 3, 7 | subadd2d 8209 | . . . 4 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → ((𝑁 − 1) = (2 · 𝑛) ↔ ((2 · 𝑛) + 1) = 𝑁)) |
9 | eqcom 2159 | . . . . 5 ⊢ ((𝑁 − 1) = (2 · 𝑛) ↔ (2 · 𝑛) = (𝑁 − 1)) | |
10 | 4, 6 | mulcomd 7901 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) → (2 · 𝑛) = (𝑛 · 2)) |
11 | 10 | eqeq1d 2166 | . . . . 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 2454 | . 2 ⊢ (𝑁 ∈ ℤ → (∃𝑛 ∈ ℤ ((2 · 𝑛) + 1) = 𝑁 ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = (𝑁 − 1))) |
15 | odd2np1 11776 | . 2 ⊢ (𝑁 ∈ ℤ → (¬ 2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ ((2 · 𝑛) + 1) = 𝑁)) | |
16 | 2z 9200 | . . 3 ⊢ 2 ∈ ℤ | |
17 | peano2zm 9210 | . . 3 ⊢ (𝑁 ∈ ℤ → (𝑁 − 1) ∈ ℤ) | |
18 | divides 11696 | . . 3 ⊢ ((2 ∈ ℤ ∧ (𝑁 − 1) ∈ ℤ) → (2 ∥ (𝑁 − 1) ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = (𝑁 − 1))) | |
19 | 16, 17, 18 | sylancr 411 | . 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 1335 ∈ wcel 2128 ∃wrex 2436 class class class wbr 3967 (class class class)co 5826 1c1 7735 + caddc 7737 · cmul 7739 − cmin 8050 2c2 8889 ℤcz 9172 ∥ cdvds 11694 |
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 604 ax-in2 605 ax-io 699 ax-5 1427 ax-7 1428 ax-gen 1429 ax-ie1 1473 ax-ie2 1474 ax-8 1484 ax-10 1485 ax-11 1486 ax-i12 1487 ax-bndl 1489 ax-4 1490 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-13 2130 ax-14 2131 ax-ext 2139 ax-sep 4084 ax-pow 4137 ax-pr 4171 ax-un 4395 ax-setind 4498 ax-cnex 7825 ax-resscn 7826 ax-1cn 7827 ax-1re 7828 ax-icn 7829 ax-addcl 7830 ax-addrcl 7831 ax-mulcl 7832 ax-mulrcl 7833 ax-addcom 7834 ax-mulcom 7835 ax-addass 7836 ax-mulass 7837 ax-distr 7838 ax-i2m1 7839 ax-0lt1 7840 ax-1rid 7841 ax-0id 7842 ax-rnegex 7843 ax-precex 7844 ax-cnre 7845 ax-pre-ltirr 7846 ax-pre-ltwlin 7847 ax-pre-lttrn 7848 ax-pre-apti 7849 ax-pre-ltadd 7850 ax-pre-mulgt0 7851 ax-pre-mulext 7852 |
This theorem depends on definitions: df-bi 116 df-3or 964 df-3an 965 df-tru 1338 df-fal 1341 df-xor 1358 df-nf 1441 df-sb 1743 df-eu 2009 df-mo 2010 df-clab 2144 df-cleq 2150 df-clel 2153 df-nfc 2288 df-ne 2328 df-nel 2423 df-ral 2440 df-rex 2441 df-reu 2442 df-rmo 2443 df-rab 2444 df-v 2714 df-sbc 2938 df-dif 3104 df-un 3106 df-in 3108 df-ss 3115 df-pw 3546 df-sn 3567 df-pr 3568 df-op 3570 df-uni 3775 df-int 3810 df-br 3968 df-opab 4028 df-id 4255 df-po 4258 df-iso 4259 df-xp 4594 df-rel 4595 df-cnv 4596 df-co 4597 df-dm 4598 df-iota 5137 df-fun 5174 df-fv 5180 df-riota 5782 df-ov 5829 df-oprab 5830 df-mpo 5831 df-pnf 7916 df-mnf 7917 df-xr 7918 df-ltxr 7919 df-le 7920 df-sub 8052 df-neg 8053 df-reap 8454 df-ap 8461 df-div 8550 df-inn 8839 df-2 8897 df-n0 9096 df-z 9173 df-dvds 11695 |
This theorem is referenced by: oddp1even 11779 n2dvds3 11818 oddennn 12191 |
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