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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 453 | . . 3 ⊢ ((𝑀 = 0 ∧ 𝑁 = 0) ↔ (𝑁 = 0 ∧ 𝑀 = 0)) | |
2 | ancom 453 | . . . . 5 ⊢ ((𝑛 ∥ 𝑀 ∧ 𝑛 ∥ 𝑁) ↔ (𝑛 ∥ 𝑁 ∧ 𝑛 ∥ 𝑀)) | |
3 | 2 | rabbii 3400 | . . . 4 ⊢ {𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑀 ∧ 𝑛 ∥ 𝑁)} = {𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑁 ∧ 𝑛 ∥ 𝑀)} |
4 | 3 | supeq1i 8706 | . . 3 ⊢ sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑀 ∧ 𝑛 ∥ 𝑁)}, ℝ, < ) = sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑁 ∧ 𝑛 ∥ 𝑀)}, ℝ, < ) |
5 | 1, 4 | ifbieq2i 4374 | . 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 15705 | . 2 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) = if((𝑀 = 0 ∧ 𝑁 = 0), 0, sup({𝑛 ∈ ℤ ∣ (𝑛 ∥ 𝑀 ∧ 𝑛 ∥ 𝑁)}, ℝ, < ))) | |
7 | gcdval 15705 | . . 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 451 | . 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 2841 | 1 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) = (𝑁 gcd 𝑀)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 387 = wceq 1507 ∈ wcel 2050 {crab 3093 ifcif 4350 class class class wbr 4929 (class class class)co 6976 supcsup 8699 ℝcr 10334 0cc0 10335 < clt 10474 ℤcz 11793 ∥ cdvds 15467 gcd cgcd 15703 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1758 ax-4 1772 ax-5 1869 ax-6 1928 ax-7 1965 ax-8 2052 ax-9 2059 ax-10 2079 ax-11 2093 ax-12 2106 ax-13 2301 ax-ext 2751 ax-sep 5060 ax-nul 5067 ax-pow 5119 ax-pr 5186 ax-un 7279 ax-resscn 10392 ax-1cn 10393 ax-icn 10394 ax-addcl 10395 ax-mulcl 10397 ax-i2m1 10403 ax-pre-lttri 10409 ax-pre-lttrn 10410 |
This theorem depends on definitions: df-bi 199 df-an 388 df-or 834 df-3or 1069 df-3an 1070 df-tru 1510 df-ex 1743 df-nf 1747 df-sb 2016 df-mo 2547 df-eu 2584 df-clab 2760 df-cleq 2772 df-clel 2847 df-nfc 2919 df-ne 2969 df-nel 3075 df-ral 3094 df-rex 3095 df-rmo 3097 df-rab 3098 df-v 3418 df-sbc 3683 df-csb 3788 df-dif 3833 df-un 3835 df-in 3837 df-ss 3844 df-nul 4180 df-if 4351 df-pw 4424 df-sn 4442 df-pr 4444 df-op 4448 df-uni 4713 df-br 4930 df-opab 4992 df-mpt 5009 df-id 5312 df-po 5326 df-so 5327 df-xp 5413 df-rel 5414 df-cnv 5415 df-co 5416 df-dm 5417 df-rn 5418 df-res 5419 df-ima 5420 df-iota 6152 df-fun 6190 df-fn 6191 df-f 6192 df-f1 6193 df-fo 6194 df-f1o 6195 df-fv 6196 df-ov 6979 df-oprab 6980 df-mpo 6981 df-er 8089 df-en 8307 df-dom 8308 df-sdom 8309 df-sup 8701 df-pnf 10476 df-mnf 10477 df-ltxr 10479 df-gcd 15704 |
This theorem is referenced by: divgcdnnr 15724 gcdid0 15728 neggcd 15731 gcdabs2 15739 modgcd 15740 1gcd 15741 6gcd4e2 15742 rplpwr 15763 rppwr 15764 eucalginv 15784 3lcm2e6woprm 15815 coprmdvds 15853 qredeq 15857 coprmprod 15861 divgcdcoprmex 15866 cncongr1 15867 rpexp12i 15922 cncongrprm 15925 phiprmpw 15969 eulerthlem1 15974 eulerthlem2 15975 fermltl 15977 prmdiv 15978 vfermltl 15994 coprimeprodsq 16001 coprimeprodsq2 16002 pythagtriplem3 16011 pythagtrip 16027 pcgcd 16070 prmpwdvds 16096 pockthlem 16097 prmgaplem7 16249 gcdi 16265 gcdmodi 16266 1259lem5 16324 2503lem3 16328 4001lem4 16333 odinv 18449 gexexlem 18728 ablfacrp2 18939 pgpfac1lem2 18947 dvdsmulf1o 25473 perfect1 25506 perfectlem1 25507 lgslem1 25575 lgsprme0 25617 lgsdirnn0 25622 lgsqrlem2 25625 lgsqr 25629 gausslemma2dlem0c 25636 lgsquad2lem2 25663 lgsquad2 25664 lgsquad3 25665 2sqlem8 25704 2sqmod 25714 ex-gcd 28014 gcd32 32500 nn0prpwlem 33188 jm2.19lem2 38980 jm2.20nn 38987 goldbachthlem2 43074 goldbachth 43075 gcd2odd1 43199 perfectALTVlem1 43252 fpprwpprb 43271 |
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