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Mirrors > Home > MPE Home > Th. List > Mathboxes > nnoALTV | Structured version Visualization version GIF version |
Description: An alternate characterization of an odd number greater than 1. (Contributed by AV, 2-Jun-2020.) (Revised by AV, 21-Jun-2020.) |
Ref | Expression |
---|---|
nnoALTV | ⊢ ((𝑁 ∈ (ℤ≥‘2) ∧ 𝑁 ∈ Odd ) → ((𝑁 − 1) / 2) ∈ ℕ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | oddm1div2z 44702 | . . 3 ⊢ (𝑁 ∈ Odd → ((𝑁 − 1) / 2) ∈ ℤ) | |
2 | 1 | adantl 485 | . 2 ⊢ ((𝑁 ∈ (ℤ≥‘2) ∧ 𝑁 ∈ Odd ) → ((𝑁 − 1) / 2) ∈ ℤ) |
3 | eluz2b1 12480 | . . . 4 ⊢ (𝑁 ∈ (ℤ≥‘2) ↔ (𝑁 ∈ ℤ ∧ 1 < 𝑁)) | |
4 | 1red 10799 | . . . . . . 7 ⊢ (𝑁 ∈ ℤ → 1 ∈ ℝ) | |
5 | zre 12145 | . . . . . . 7 ⊢ (𝑁 ∈ ℤ → 𝑁 ∈ ℝ) | |
6 | 4, 5 | posdifd 11384 | . . . . . 6 ⊢ (𝑁 ∈ ℤ → (1 < 𝑁 ↔ 0 < (𝑁 − 1))) |
7 | 6 | biimpa 480 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 1 < 𝑁) → 0 < (𝑁 − 1)) |
8 | peano2zm 12185 | . . . . . . . . 9 ⊢ (𝑁 ∈ ℤ → (𝑁 − 1) ∈ ℤ) | |
9 | 8 | zred 12247 | . . . . . . . 8 ⊢ (𝑁 ∈ ℤ → (𝑁 − 1) ∈ ℝ) |
10 | 2re 11869 | . . . . . . . . 9 ⊢ 2 ∈ ℝ | |
11 | 10 | a1i 11 | . . . . . . . 8 ⊢ (𝑁 ∈ ℤ → 2 ∈ ℝ) |
12 | 2pos 11898 | . . . . . . . . 9 ⊢ 0 < 2 | |
13 | 12 | a1i 11 | . . . . . . . 8 ⊢ (𝑁 ∈ ℤ → 0 < 2) |
14 | 9, 11, 13 | 3jca 1130 | . . . . . . 7 ⊢ (𝑁 ∈ ℤ → ((𝑁 − 1) ∈ ℝ ∧ 2 ∈ ℝ ∧ 0 < 2)) |
15 | 14 | adantr 484 | . . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 1 < 𝑁) → ((𝑁 − 1) ∈ ℝ ∧ 2 ∈ ℝ ∧ 0 < 2)) |
16 | gt0div 11663 | . . . . . 6 ⊢ (((𝑁 − 1) ∈ ℝ ∧ 2 ∈ ℝ ∧ 0 < 2) → (0 < (𝑁 − 1) ↔ 0 < ((𝑁 − 1) / 2))) | |
17 | 15, 16 | syl 17 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 1 < 𝑁) → (0 < (𝑁 − 1) ↔ 0 < ((𝑁 − 1) / 2))) |
18 | 7, 17 | mpbid 235 | . . . 4 ⊢ ((𝑁 ∈ ℤ ∧ 1 < 𝑁) → 0 < ((𝑁 − 1) / 2)) |
19 | 3, 18 | sylbi 220 | . . 3 ⊢ (𝑁 ∈ (ℤ≥‘2) → 0 < ((𝑁 − 1) / 2)) |
20 | 19 | adantr 484 | . 2 ⊢ ((𝑁 ∈ (ℤ≥‘2) ∧ 𝑁 ∈ Odd ) → 0 < ((𝑁 − 1) / 2)) |
21 | elnnz 12151 | . 2 ⊢ (((𝑁 − 1) / 2) ∈ ℕ ↔ (((𝑁 − 1) / 2) ∈ ℤ ∧ 0 < ((𝑁 − 1) / 2))) | |
22 | 2, 20, 21 | sylanbrc 586 | 1 ⊢ ((𝑁 ∈ (ℤ≥‘2) ∧ 𝑁 ∈ Odd ) → ((𝑁 − 1) / 2) ∈ ℕ) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 209 ∧ wa 399 ∧ w3a 1089 ∈ wcel 2112 class class class wbr 5039 ‘cfv 6358 (class class class)co 7191 ℝcr 10693 0cc0 10694 1c1 10695 < clt 10832 − cmin 11027 / cdiv 11454 ℕcn 11795 2c2 11850 ℤcz 12141 ℤ≥cuz 12403 Odd codd 44693 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1803 ax-4 1817 ax-5 1918 ax-6 1976 ax-7 2018 ax-8 2114 ax-9 2122 ax-10 2143 ax-11 2160 ax-12 2177 ax-ext 2708 ax-sep 5177 ax-nul 5184 ax-pow 5243 ax-pr 5307 ax-un 7501 ax-cnex 10750 ax-resscn 10751 ax-1cn 10752 ax-icn 10753 ax-addcl 10754 ax-addrcl 10755 ax-mulcl 10756 ax-mulrcl 10757 ax-mulcom 10758 ax-addass 10759 ax-mulass 10760 ax-distr 10761 ax-i2m1 10762 ax-1ne0 10763 ax-1rid 10764 ax-rnegex 10765 ax-rrecex 10766 ax-cnre 10767 ax-pre-lttri 10768 ax-pre-lttrn 10769 ax-pre-ltadd 10770 ax-pre-mulgt0 10771 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 848 df-3or 1090 df-3an 1091 df-tru 1546 df-fal 1556 df-ex 1788 df-nf 1792 df-sb 2073 df-mo 2539 df-eu 2568 df-clab 2715 df-cleq 2728 df-clel 2809 df-nfc 2879 df-ne 2933 df-nel 3037 df-ral 3056 df-rex 3057 df-reu 3058 df-rmo 3059 df-rab 3060 df-v 3400 df-sbc 3684 df-csb 3799 df-dif 3856 df-un 3858 df-in 3860 df-ss 3870 df-pss 3872 df-nul 4224 df-if 4426 df-pw 4501 df-sn 4528 df-pr 4530 df-tp 4532 df-op 4534 df-uni 4806 df-iun 4892 df-br 5040 df-opab 5102 df-mpt 5121 df-tr 5147 df-id 5440 df-eprel 5445 df-po 5453 df-so 5454 df-fr 5494 df-we 5496 df-xp 5542 df-rel 5543 df-cnv 5544 df-co 5545 df-dm 5546 df-rn 5547 df-res 5548 df-ima 5549 df-pred 6140 df-ord 6194 df-on 6195 df-lim 6196 df-suc 6197 df-iota 6316 df-fun 6360 df-fn 6361 df-f 6362 df-f1 6363 df-fo 6364 df-f1o 6365 df-fv 6366 df-riota 7148 df-ov 7194 df-oprab 7195 df-mpo 7196 df-om 7623 df-wrecs 8025 df-recs 8086 df-rdg 8124 df-er 8369 df-en 8605 df-dom 8606 df-sdom 8607 df-pnf 10834 df-mnf 10835 df-xr 10836 df-ltxr 10837 df-le 10838 df-sub 11029 df-neg 11030 df-div 11455 df-nn 11796 df-2 11858 df-n0 12056 df-z 12142 df-uz 12404 df-odd 44695 |
This theorem is referenced by: (None) |
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