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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 14898 | . 2 ⊢ (2 ∥ 𝑁 → 𝑁 ∈ ℤ) | |
2 | 2z 11286 | . . . . . . 7 ⊢ 2 ∈ ℤ | |
3 | 2 | a1i 11 | . . . . . 6 ⊢ (𝑛 ∈ ℤ → 2 ∈ ℤ) |
4 | id 22 | . . . . . 6 ⊢ (𝑛 ∈ ℤ → 𝑛 ∈ ℤ) | |
5 | 3, 4 | zmulcld 11364 | . . . . 5 ⊢ (𝑛 ∈ ℤ → (2 · 𝑛) ∈ ℤ) |
6 | 5 | adantr 480 | . . . 4 ⊢ ((𝑛 ∈ ℤ ∧ (2 · 𝑛) = 𝑁) → (2 · 𝑛) ∈ ℤ) |
7 | eleq1 2676 | . . . . 5 ⊢ ((2 · 𝑛) = 𝑁 → ((2 · 𝑛) ∈ ℤ ↔ 𝑁 ∈ ℤ)) | |
8 | 7 | adantl 481 | . . . 4 ⊢ ((𝑛 ∈ ℤ ∧ (2 · 𝑛) = 𝑁) → ((2 · 𝑛) ∈ ℤ ↔ 𝑁 ∈ ℤ)) |
9 | 6, 8 | mpbid 221 | . . 3 ⊢ ((𝑛 ∈ ℤ ∧ (2 · 𝑛) = 𝑁) → 𝑁 ∈ ℤ) |
10 | 9 | rexlimiva 3010 | . 2 ⊢ (∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁 → 𝑁 ∈ ℤ) |
11 | divides 14823 | . . . 4 ⊢ ((2 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ (𝑛 · 2) = 𝑁)) | |
12 | zcn 11259 | . . . . . . 7 ⊢ (𝑛 ∈ ℤ → 𝑛 ∈ ℂ) | |
13 | 2cnd 10970 | . . . . . . 7 ⊢ (𝑛 ∈ ℤ → 2 ∈ ℂ) | |
14 | 12, 13 | mulcomd 9940 | . . . . . 6 ⊢ (𝑛 ∈ ℤ → (𝑛 · 2) = (2 · 𝑛)) |
15 | 14 | eqeq1d 2612 | . . . . 5 ⊢ (𝑛 ∈ ℤ → ((𝑛 · 2) = 𝑁 ↔ (2 · 𝑛) = 𝑁)) |
16 | 15 | rexbiia 3022 | . . . 4 ⊢ (∃𝑛 ∈ ℤ (𝑛 · 2) = 𝑁 ↔ ∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁) |
17 | 11, 16 | syl6bb 275 | . . 3 ⊢ ((2 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁)) |
18 | 2, 17 | mpan 702 | . 2 ⊢ (𝑁 ∈ ℤ → (2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁)) |
19 | 1, 10, 18 | pm5.21nii 367 | 1 ⊢ (2 ∥ 𝑁 ↔ ∃𝑛 ∈ ℤ (2 · 𝑛) = 𝑁) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 195 ∧ wa 383 = wceq 1475 ∈ wcel 1977 ∃wrex 2897 class class class wbr 4583 (class class class)co 6549 · cmul 9820 2c2 10947 ℤcz 11254 ∥ cdvds 14821 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 ax-5 1827 ax-6 1875 ax-7 1922 ax-8 1979 ax-9 1986 ax-10 2006 ax-11 2021 ax-12 2034 ax-13 2234 ax-ext 2590 ax-sep 4709 ax-nul 4717 ax-pow 4769 ax-pr 4833 ax-un 6847 ax-resscn 9872 ax-1cn 9873 ax-icn 9874 ax-addcl 9875 ax-addrcl 9876 ax-mulcl 9877 ax-mulrcl 9878 ax-mulcom 9879 ax-addass 9880 ax-mulass 9881 ax-distr 9882 ax-i2m1 9883 ax-1ne0 9884 ax-1rid 9885 ax-rnegex 9886 ax-rrecex 9887 ax-cnre 9888 ax-pre-lttri 9889 ax-pre-lttrn 9890 ax-pre-ltadd 9891 ax-pre-mulgt0 9892 |
This theorem depends on definitions: df-bi 196 df-or 384 df-an 385 df-3or 1032 df-3an 1033 df-tru 1478 df-ex 1696 df-nf 1701 df-sb 1868 df-eu 2462 df-mo 2463 df-clab 2597 df-cleq 2603 df-clel 2606 df-nfc 2740 df-ne 2782 df-nel 2783 df-ral 2901 df-rex 2902 df-reu 2903 df-rab 2905 df-v 3175 df-sbc 3403 df-csb 3500 df-dif 3543 df-un 3545 df-in 3547 df-ss 3554 df-pss 3556 df-nul 3875 df-if 4037 df-pw 4110 df-sn 4126 df-pr 4128 df-tp 4130 df-op 4132 df-uni 4373 df-iun 4457 df-br 4584 df-opab 4644 df-mpt 4645 df-tr 4681 df-eprel 4949 df-id 4953 df-po 4959 df-so 4960 df-fr 4997 df-we 4999 df-xp 5044 df-rel 5045 df-cnv 5046 df-co 5047 df-dm 5048 df-rn 5049 df-res 5050 df-ima 5051 df-pred 5597 df-ord 5643 df-on 5644 df-lim 5645 df-suc 5646 df-iota 5768 df-fun 5806 df-fn 5807 df-f 5808 df-f1 5809 df-fo 5810 df-f1o 5811 df-fv 5812 df-riota 6511 df-ov 6552 df-oprab 6553 df-mpt2 6554 df-om 6958 df-wrecs 7294 df-recs 7355 df-rdg 7393 df-er 7629 df-en 7842 df-dom 7843 df-sdom 7844 df-pnf 9955 df-mnf 9956 df-xr 9957 df-ltxr 9958 df-le 9959 df-sub 10147 df-neg 10148 df-nn 10898 df-2 10956 df-n0 11170 df-z 11255 df-dvds 14822 |
This theorem is referenced by: evennn02n 14912 evennn2n 14913 m1expe 14929 |
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