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Mirrors > Home > MPE Home > Th. List > even2n | Structured version Visualization version GIF version |
Description: An integer is even iff it is twice another integer. (Contributed by AV, 25-Jun-2020.) |
Ref | Expression |
---|---|
even2n | ⊢ (2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | evenelz 15060 | . 2 ⊢ (2 ∥ 𝑁 → 𝑁 ∈ ℤ) | |
2 | 2z 11409 | . . . . . . 7 ⊢ 2 ∈ ℤ | |
3 | 2 | a1i 11 | . . . . . 6 ⊢ (𝑛 ∈ ℤ → 2 ∈ ℤ) |
4 | id 22 | . . . . . 6 ⊢ (𝑛 ∈ ℤ → 𝑛 ∈ ℤ) | |
5 | 3, 4 | zmulcld 11488 | . . . . 5 ⊢ (𝑛 ∈ ℤ → (2 · 𝑛) ∈ ℤ) |
6 | 5 | adantr 481 | . . . 4 ⊢ ((𝑛 ∈ ℤ ∧ (2 · 𝑛) = 𝑁) → (2 · 𝑛) ∈ ℤ) |
7 | eleq1 2689 | . . . . 5 ⊢ ((2 · 𝑛) = 𝑁 → ((2 · 𝑛) ∈ ℤ ↔ 𝑁 ∈ ℤ)) | |
8 | 7 | adantl 482 | . . . 4 ⊢ ((𝑛 ∈ ℤ ∧ (2 · 𝑛) = 𝑁) → ((2 · 𝑛) ∈ ℤ ↔ 𝑁 ∈ ℤ)) |
9 | 6, 8 | mpbid 222 | . . 3 ⊢ ((𝑛 ∈ ℤ ∧ (2 · 𝑛) = 𝑁) → 𝑁 ∈ ℤ) |
10 | 9 | rexlimiva 3028 | . 2 ⊢ (∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁 → 𝑁 ∈ ℤ) |
11 | divides 14985 | . . . 4 ⊢ ((2 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = 𝑁)) | |
12 | zcn 11382 | . . . . . . 7 ⊢ (𝑛 ∈ ℤ → 𝑛 ∈ ℂ) | |
13 | 2cnd 11093 | . . . . . . 7 ⊢ (𝑛 ∈ ℤ → 2 ∈ ℂ) | |
14 | 12, 13 | mulcomd 10061 | . . . . . 6 ⊢ (𝑛 ∈ ℤ → (𝑛 · 2) = (2 · 𝑛)) |
15 | 14 | eqeq1d 2624 | . . . . 5 ⊢ (𝑛 ∈ ℤ → ((𝑛 · 2) = 𝑁 ↔ (2 · 𝑛) = 𝑁)) |
16 | 15 | rexbiia 3040 | . . . 4 ⊢ (∃𝑛 ∈ ℤ (𝑛 · 2) = 𝑁 ↔ ∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁) |
17 | 11, 16 | syl6bb 276 | . . 3 ⊢ ((2 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁)) |
18 | 2, 17 | mpan 706 | . 2 ⊢ (𝑁 ∈ ℤ → (2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁)) |
19 | 1, 10, 18 | pm5.21nii 368 | 1 ⊢ (2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 196 ∧ wa 384 = wceq 1483 ∈ wcel 1990 ∃wrex 2913 class class class wbr 4653 (class class class)co 6650 · cmul 9941 2c2 11070 ℤcz 11377 ∥ cdvds 14983 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-8 1992 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 ax-sep 4781 ax-nul 4789 ax-pow 4843 ax-pr 4906 ax-un 6949 ax-resscn 9993 ax-1cn 9994 ax-icn 9995 ax-addcl 9996 ax-addrcl 9997 ax-mulcl 9998 ax-mulrcl 9999 ax-mulcom 10000 ax-addass 10001 ax-mulass 10002 ax-distr 10003 ax-i2m1 10004 ax-1ne0 10005 ax-1rid 10006 ax-rnegex 10007 ax-rrecex 10008 ax-cnre 10009 ax-pre-lttri 10010 ax-pre-lttrn 10011 ax-pre-ltadd 10012 ax-pre-mulgt0 10013 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3or 1038 df-3an 1039 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-eu 2474 df-mo 2475 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-ne 2795 df-nel 2898 df-ral 2917 df-rex 2918 df-reu 2919 df-rab 2921 df-v 3202 df-sbc 3436 df-csb 3534 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-pss 3590 df-nul 3916 df-if 4087 df-pw 4160 df-sn 4178 df-pr 4180 df-tp 4182 df-op 4184 df-uni 4437 df-iun 4522 df-br 4654 df-opab 4713 df-mpt 4730 df-tr 4753 df-id 5024 df-eprel 5029 df-po 5035 df-so 5036 df-fr 5073 df-we 5075 df-xp 5120 df-rel 5121 df-cnv 5122 df-co 5123 df-dm 5124 df-rn 5125 df-res 5126 df-ima 5127 df-pred 5680 df-ord 5726 df-on 5727 df-lim 5728 df-suc 5729 df-iota 5851 df-fun 5890 df-fn 5891 df-f 5892 df-f1 5893 df-fo 5894 df-f1o 5895 df-fv 5896 df-riota 6611 df-ov 6653 df-oprab 6654 df-mpt2 6655 df-om 7066 df-wrecs 7407 df-recs 7468 df-rdg 7506 df-er 7742 df-en 7956 df-dom 7957 df-sdom 7958 df-pnf 10076 df-mnf 10077 df-xr 10078 df-ltxr 10079 df-le 10080 df-sub 10268 df-neg 10269 df-nn 11021 df-2 11079 df-n0 11293 df-z 11378 df-dvds 14984 |
This theorem is referenced by: evennn02n 15074 evennn2n 15075 m1expe 15091 |
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