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Mirrors > Home > ILE Home > Th. List > zneo | GIF version |
Description: No even integer equals an odd integer (i.e. no integer can be both even and odd). Exercise 10(a) of [Apostol] p. 28. (Contributed by NM, 31-Jul-2004.) (Proof shortened by Mario Carneiro, 18-May-2014.) |
Ref | Expression |
---|---|
zneo | ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (2 · 𝐴) ≠ ((2 · 𝐵) + 1)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | halfnz 9367 | . . 3 ⊢ ¬ (1 / 2) ∈ ℤ | |
2 | 2cn 9008 | . . . . . . 7 ⊢ 2 ∈ ℂ | |
3 | zcn 9276 | . . . . . . . 8 ⊢ (𝐴 ∈ ℤ → 𝐴 ∈ ℂ) | |
4 | 3 | adantr 276 | . . . . . . 7 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → 𝐴 ∈ ℂ) |
5 | mulcl 7956 | . . . . . . 7 ⊢ ((2 ∈ ℂ ∧ 𝐴 ∈ ℂ) → (2 · 𝐴) ∈ ℂ) | |
6 | 2, 4, 5 | sylancr 414 | . . . . . 6 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (2 · 𝐴) ∈ ℂ) |
7 | zcn 9276 | . . . . . . . 8 ⊢ (𝐵 ∈ ℤ → 𝐵 ∈ ℂ) | |
8 | 7 | adantl 277 | . . . . . . 7 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → 𝐵 ∈ ℂ) |
9 | mulcl 7956 | . . . . . . 7 ⊢ ((2 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (2 · 𝐵) ∈ ℂ) | |
10 | 2, 8, 9 | sylancr 414 | . . . . . 6 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (2 · 𝐵) ∈ ℂ) |
11 | 1cnd 7991 | . . . . . 6 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → 1 ∈ ℂ) | |
12 | 6, 10, 11 | subaddd 8304 | . . . . 5 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (((2 · 𝐴) − (2 · 𝐵)) = 1 ↔ ((2 · 𝐵) + 1) = (2 · 𝐴))) |
13 | 2 | a1i 9 | . . . . . . . . . 10 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → 2 ∈ ℂ) |
14 | 13, 4, 8 | subdid 8389 | . . . . . . . . 9 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (2 · (𝐴 − 𝐵)) = ((2 · 𝐴) − (2 · 𝐵))) |
15 | 14 | oveq1d 5906 | . . . . . . . 8 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → ((2 · (𝐴 − 𝐵)) / 2) = (((2 · 𝐴) − (2 · 𝐵)) / 2)) |
16 | zsubcl 9312 | . . . . . . . . . 10 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (𝐴 − 𝐵) ∈ ℤ) | |
17 | zcn 9276 | . . . . . . . . . 10 ⊢ ((𝐴 − 𝐵) ∈ ℤ → (𝐴 − 𝐵) ∈ ℂ) | |
18 | 16, 17 | syl 14 | . . . . . . . . 9 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (𝐴 − 𝐵) ∈ ℂ) |
19 | 2ap0 9030 | . . . . . . . . . 10 ⊢ 2 # 0 | |
20 | 19 | a1i 9 | . . . . . . . . 9 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → 2 # 0) |
21 | 18, 13, 20 | divcanap3d 8770 | . . . . . . . 8 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → ((2 · (𝐴 − 𝐵)) / 2) = (𝐴 − 𝐵)) |
22 | 15, 21 | eqtr3d 2224 | . . . . . . 7 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (((2 · 𝐴) − (2 · 𝐵)) / 2) = (𝐴 − 𝐵)) |
23 | 22, 16 | eqeltrd 2266 | . . . . . 6 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (((2 · 𝐴) − (2 · 𝐵)) / 2) ∈ ℤ) |
24 | oveq1 5898 | . . . . . . 7 ⊢ (((2 · 𝐴) − (2 · 𝐵)) = 1 → (((2 · 𝐴) − (2 · 𝐵)) / 2) = (1 / 2)) | |
25 | 24 | eleq1d 2258 | . . . . . 6 ⊢ (((2 · 𝐴) − (2 · 𝐵)) = 1 → ((((2 · 𝐴) − (2 · 𝐵)) / 2) ∈ ℤ ↔ (1 / 2) ∈ ℤ)) |
26 | 23, 25 | syl5ibcom 155 | . . . . 5 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (((2 · 𝐴) − (2 · 𝐵)) = 1 → (1 / 2) ∈ ℤ)) |
27 | 12, 26 | sylbird 170 | . . . 4 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (((2 · 𝐵) + 1) = (2 · 𝐴) → (1 / 2) ∈ ℤ)) |
28 | 27 | necon3bd 2403 | . . 3 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (¬ (1 / 2) ∈ ℤ → ((2 · 𝐵) + 1) ≠ (2 · 𝐴))) |
29 | 1, 28 | mpi 15 | . 2 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → ((2 · 𝐵) + 1) ≠ (2 · 𝐴)) |
30 | 29 | necomd 2446 | 1 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (2 · 𝐴) ≠ ((2 · 𝐵) + 1)) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 104 = wceq 1364 ∈ wcel 2160 ≠ wne 2360 class class class wbr 4018 (class class class)co 5891 ℂcc 7827 0cc0 7829 1c1 7830 + caddc 7832 · cmul 7834 − cmin 8146 # cap 8556 / cdiv 8647 2c2 8988 ℤcz 9271 |
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-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 |
This theorem is referenced by: nneo 9374 zeo2 9377 |
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