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Mirrors > Home > MPE Home > Th. List > gcdcom | Structured version Visualization version GIF version |
Description: The gcd operator is commutative. Theorem 1.4(a) in [ApostolNT] p. 16. (Contributed by Paul Chapman, 21-Mar-2011.) |
Ref | Expression |
---|---|
gcdcom | ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) = (𝑁 gcd 𝑀)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ancom 460 | . . 3 ⊢ ((𝑀 = 0 ∧ 𝑁 = 0) ↔ (𝑁 = 0 ∧ 𝑀 = 0)) | |
2 | ancom 460 | . . . . 5 ⊢ ((𝑛 ∥ 𝑀 ∧ 𝑛 ∥ 𝑁) ↔ (𝑛 ∥ 𝑁 ∧ 𝑛 ∥ 𝑀)) | |
3 | 2 | rabbii 3438 | . . . 4 ⊢ {𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑀 ∧ 𝑛 ∥ 𝑁)} = {𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑁 ∧ 𝑛 ∥ 𝑀)} |
4 | 3 | supeq1i 9484 | . . 3 ⊢ sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑀 ∧ 𝑛 ∥ 𝑁)}, ℝ, < ) = sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑁 ∧ 𝑛 ∥ 𝑀)}, ℝ, < ) |
5 | 1, 4 | ifbieq2i 4555 | . 2 ⊢ if((𝑀 = 0 ∧ 𝑁 = 0), 0, sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑀 ∧ 𝑛 ∥ 𝑁)}, ℝ, < )) = if((𝑁 = 0 ∧ 𝑀 = 0), 0, sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑁 ∧ 𝑛 ∥ 𝑀)}, ℝ, < )) |
6 | gcdval 16529 | . 2 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) = if((𝑀 = 0 ∧ 𝑁 = 0), 0, sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑀 ∧ 𝑛 ∥ 𝑁)}, ℝ, < ))) | |
7 | gcdval 16529 | . . 3 ⊢ ((𝑁 ∈ ℤ ∧ 𝑀 ∈ ℤ) → (𝑁 gcd 𝑀) = if((𝑁 = 0 ∧ 𝑀 = 0), 0, sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑁 ∧ 𝑛 ∥ 𝑀)}, ℝ, < ))) | |
8 | 7 | ancoms 458 | . 2 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑁 gcd 𝑀) = if((𝑁 = 0 ∧ 𝑀 = 0), 0, sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑁 ∧ 𝑛 ∥ 𝑀)}, ℝ, < ))) |
9 | 5, 6, 8 | 3eqtr4a 2800 | 1 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) = (𝑁 gcd 𝑀)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 395 = wceq 1536 ∈ wcel 2105 {crab 3432 ifcif 4530 class class class wbr 5147 (class class class)co 7430 supcsup 9477 ℝcr 11151 0cc0 11152 < clt 11292 ℤcz 12610 ∥ cdvds 16286 gcd cgcd 16527 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1791 ax-4 1805 ax-5 1907 ax-6 1964 ax-7 2004 ax-8 2107 ax-9 2115 ax-10 2138 ax-11 2154 ax-12 2174 ax-ext 2705 ax-sep 5301 ax-nul 5311 ax-pow 5370 ax-pr 5437 ax-un 7753 ax-resscn 11209 ax-1cn 11210 ax-icn 11211 ax-addcl 11212 ax-mulcl 11214 ax-i2m1 11220 ax-pre-lttri 11226 ax-pre-lttrn 11227 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1539 df-fal 1549 df-ex 1776 df-nf 1780 df-sb 2062 df-mo 2537 df-eu 2566 df-clab 2712 df-cleq 2726 df-clel 2813 df-nfc 2889 df-ne 2938 df-nel 3044 df-ral 3059 df-rex 3068 df-rmo 3377 df-rab 3433 df-v 3479 df-sbc 3791 df-csb 3908 df-dif 3965 df-un 3967 df-in 3969 df-ss 3979 df-nul 4339 df-if 4531 df-pw 4606 df-sn 4631 df-pr 4633 df-op 4637 df-uni 4912 df-br 5148 df-opab 5210 df-mpt 5231 df-id 5582 df-po 5596 df-so 5597 df-xp 5694 df-rel 5695 df-cnv 5696 df-co 5697 df-dm 5698 df-rn 5699 df-res 5700 df-ima 5701 df-iota 6515 df-fun 6564 df-fn 6565 df-f 6566 df-f1 6567 df-fo 6568 df-f1o 6569 df-fv 6570 df-ov 7433 df-oprab 7434 df-mpo 7435 df-er 8743 df-en 8984 df-dom 8985 df-sdom 8986 df-sup 9479 df-pnf 11294 df-mnf 11295 df-ltxr 11297 df-gcd 16528 |
This theorem is referenced by: gcdcomd 16547 divgcdnnr 16549 gcdid0 16553 neggcd 16556 gcdabs2 16563 1gcd 16566 6gcd4e2 16571 rprpwr 16592 eucalginv 16617 3lcm2e6woprm 16648 coprmdvds 16686 qredeq 16690 divgcdcoprmex 16699 cncongr1 16700 cncongrprm 16762 fermltl 16817 vfermltl 16834 coprimeprodsq2 16842 pythagtrip 16867 pcgcd 16911 pockthlem 16938 gcdi 17106 gcdmodi 17107 1259lem5 17168 2503lem3 17172 4001lem4 17177 odinv 19593 lgsprme0 27397 lgsdirnn0 27402 lgsquad2lem2 27443 lgsquad3 27445 ex-gcd 30485 gcd32 35728 gcdcomnni 41969 aks6d1c1 42097 aks6d1c4 42105 goldbachthlem2 47470 goldbachth 47471 gcd2odd1 47592 fpprwpprb 47664 |
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