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Theorem lcmid 10687

Description: The lcm of an integer and itself is its absolute value. (Contributed by Steve Rodriguez, 20-Jan-2020.)

**Assertion**
Ref	Expression
lcmid	⊢ (𝑀 ∈ ℤ → (𝑀 lcm 𝑀) = (abs‘𝑀))

**Proof of Theorem lcmid**
Step	Hyp	Ref	Expression
1		lcm0val 10672	. . . 4 ⊢ (𝑀 ∈ ℤ → (𝑀 lcm 0) = 0)
2	1	adantr 270	. . 3 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 = 0) → (𝑀 lcm 0) = 0)
3		oveq2 5572	. . . . 5 ⊢ (𝑀 = 0 → (𝑀 lcm 𝑀) = (𝑀 lcm 0))
4		fveq2 5230	. . . . . 6 ⊢ (𝑀 = 0 → (abs‘𝑀) = (abs‘0))
5		abs0 10163	. . . . . 6 ⊢ (abs‘0) = 0
6	4, 5	syl6eq 2131	. . . . 5 ⊢ (𝑀 = 0 → (abs‘𝑀) = 0)
7	3, 6	eqeq12d 2097	. . . 4 ⊢ (𝑀 = 0 → ((𝑀 lcm 𝑀) = (abs‘𝑀) ↔ (𝑀 lcm 0) = 0))
8	7	adantl 271	. . 3 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 = 0) → ((𝑀 lcm 𝑀) = (abs‘𝑀) ↔ (𝑀 lcm 0) = 0))
9	2, 8	mpbird 165	. 2 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 = 0) → (𝑀 lcm 𝑀) = (abs‘𝑀))
10		df-ne 2250	. . 3 ⊢ (𝑀 ≠ 0 ↔ ¬ 𝑀 = 0)
11		lcmcl 10679	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ∈ ℤ) → (𝑀 lcm 𝑀) ∈ ℕ₀)
12	11	nn0cnd 8480	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ∈ ℤ) → (𝑀 lcm 𝑀) ∈ ℂ)
13	12	anidms 389	. . . . 5 ⊢ (𝑀 ∈ ℤ → (𝑀 lcm 𝑀) ∈ ℂ)
14	13	adantr 270	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → (𝑀 lcm 𝑀) ∈ ℂ)
15		zabscl 10191	. . . . . 6 ⊢ (𝑀 ∈ ℤ → (abs‘𝑀) ∈ ℤ)
16	15	zcnd 8621	. . . . 5 ⊢ (𝑀 ∈ ℤ → (abs‘𝑀) ∈ ℂ)
17	16	adantr 270	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → (abs‘𝑀) ∈ ℂ)
18		zcn 8507	. . . . . . 7 ⊢ (𝑀 ∈ ℤ → 𝑀 ∈ ℂ)
19	18	adantr 270	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → 𝑀 ∈ ℂ)
20		simpr 108	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → 𝑀 ≠ 0)
21	19, 20	absne0d 10292	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → (abs‘𝑀) ≠ 0)
22		0zd 8514	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → 0 ∈ ℤ)
23		zapne 8573	. . . . . 6 ⊢ (((abs‘𝑀) ∈ ℤ ∧ 0 ∈ ℤ) → ((abs‘𝑀) # 0 ↔ (abs‘𝑀) ≠ 0))
24	15, 22, 23	syl2an2r 560	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → ((abs‘𝑀) # 0 ↔ (abs‘𝑀) ≠ 0))
25	21, 24	mpbird 165	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → (abs‘𝑀) # 0)
26		lcmgcd 10685	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ∈ ℤ) → ((𝑀 lcm 𝑀) · (𝑀 gcd 𝑀)) = (abs‘(𝑀 · 𝑀)))
27	26	anidms 389	. . . . . 6 ⊢ (𝑀 ∈ ℤ → ((𝑀 lcm 𝑀) · (𝑀 gcd 𝑀)) = (abs‘(𝑀 · 𝑀)))
28		gcdid 10602	. . . . . . 7 ⊢ (𝑀 ∈ ℤ → (𝑀 gcd 𝑀) = (abs‘𝑀))
29	28	oveq2d 5580	. . . . . 6 ⊢ (𝑀 ∈ ℤ → ((𝑀 lcm 𝑀) · (𝑀 gcd 𝑀)) = ((𝑀 lcm 𝑀) · (abs‘𝑀)))
30	18, 18	absmuld 10299	. . . . . 6 ⊢ (𝑀 ∈ ℤ → (abs‘(𝑀 · 𝑀)) = ((abs‘𝑀) · (abs‘𝑀)))
31	27, 29, 30	3eqtr3d 2123	. . . . 5 ⊢ (𝑀 ∈ ℤ → ((𝑀 lcm 𝑀) · (abs‘𝑀)) = ((abs‘𝑀) · (abs‘𝑀)))
32	31	adantr 270	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → ((𝑀 lcm 𝑀) · (abs‘𝑀)) = ((abs‘𝑀) · (abs‘𝑀)))
33	14, 17, 17, 25, 32	mulcanap2ad 7891	. . 3 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → (𝑀 lcm 𝑀) = (abs‘𝑀))
34	10, 33	sylan2br 282	. 2 ⊢ ((𝑀 ∈ ℤ ∧ ¬ 𝑀 = 0) → (𝑀 lcm 𝑀) = (abs‘𝑀))
35		0z 8513	. . . 4 ⊢ 0 ∈ ℤ
36		zdceq 8574	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ 0 ∈ ℤ) → DECID 𝑀 = 0)
37	35, 36	mpan2 416	. . 3 ⊢ (𝑀 ∈ ℤ → DECID 𝑀 = 0)
38		exmiddc 778	. . 3 ⊢ (DECID 𝑀 = 0 → (𝑀 = 0 ∨ ¬ 𝑀 = 0))
39	37, 38	syl 14	. 2 ⊢ (𝑀 ∈ ℤ → (𝑀 = 0 ∨ ¬ 𝑀 = 0))
40	9, 34, 39	mpjaodan 745	1 ⊢ (𝑀 ∈ ℤ → (𝑀 lcm 𝑀) = (abs‘𝑀))

Colors of variables: wff set class

Syntax hints: ¬ wn 3 → wi 4 ∧ wa 102 ↔ wb 103 ∨ wo 662 DECID wdc 776 = wceq 1285 ∈ wcel 1434 ≠ wne 2249 class class class wbr 3805 ‘cfv 4952 (class class class)co 5564 ℂcc 7111 0cc0 7113 · cmul 7118 # cap 7818 ℤcz 8502 abscabs 10102 gcd cgcd 10563 lcm clcm 10667

This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 ax-ia2 105 ax-ia3 106 ax-in1 577 ax-in2 578 ax-io 663 ax-5 1377 ax-7 1378 ax-gen 1379 ax-ie1 1423 ax-ie2 1424 ax-8 1436 ax-10 1437 ax-11 1438 ax-i12 1439 ax-bndl 1440 ax-4 1441 ax-13 1445 ax-14 1446 ax-17 1460 ax-i9 1464 ax-ial 1468 ax-i5r 1469 ax-ext 2065 ax-coll 3913 ax-sep 3916 ax-nul 3924 ax-pow 3968 ax-pr 3992 ax-un 4216 ax-setind 4308 ax-iinf 4357 ax-cnex 7199 ax-resscn 7200 ax-1cn 7201 ax-1re 7202 ax-icn 7203 ax-addcl 7204 ax-addrcl 7205 ax-mulcl 7206 ax-mulrcl 7207 ax-addcom 7208 ax-mulcom 7209 ax-addass 7210 ax-mulass 7211 ax-distr 7212 ax-i2m1 7213 ax-0lt1 7214 ax-1rid 7215 ax-0id 7216 ax-rnegex 7217 ax-precex 7218 ax-cnre 7219 ax-pre-ltirr 7220 ax-pre-ltwlin 7221 ax-pre-lttrn 7222 ax-pre-apti 7223 ax-pre-ltadd 7224 ax-pre-mulgt0 7225 ax-pre-mulext 7226 ax-arch 7227 ax-caucvg 7228

This theorem depends on definitions: df-bi 115 df-dc 777 df-3or 921 df-3an 922 df-tru 1288 df-fal 1291 df-nf 1391 df-sb 1688 df-eu 1946 df-mo 1947 df-clab 2070 df-cleq 2076 df-clel 2079 df-nfc 2212 df-ne 2250 df-nel 2345 df-ral 2358 df-rex 2359 df-reu 2360 df-rmo 2361 df-rab 2362 df-v 2612 df-sbc 2825 df-csb 2918 df-dif 2984 df-un 2986 df-in 2988 df-ss 2995 df-nul 3268 df-if 3369 df-pw 3402 df-sn 3422 df-pr 3423 df-op 3425 df-uni 3622 df-int 3657 df-iun 3700 df-br 3806 df-opab 3860 df-mpt 3861 df-tr 3896 df-id 4076 df-po 4079 df-iso 4080 df-iord 4149 df-on 4151 df-ilim 4152 df-suc 4154 df-iom 4360 df-xp 4397 df-rel 4398 df-cnv 4399 df-co 4400 df-dm 4401 df-rn 4402 df-res 4403 df-ima 4404 df-iota 4917 df-fun 4954 df-fn 4955 df-f 4956 df-f1 4957 df-fo 4958 df-f1o 4959 df-fv 4960 df-isom 4961 df-riota 5520 df-ov 5567 df-oprab 5568 df-mpt2 5569 df-1st 5819 df-2nd 5820 df-recs 5975 df-frec 6061 df-sup 6492 df-inf 6493 df-pnf 7287 df-mnf 7288 df-xr 7289 df-ltxr 7290 df-le 7291 df-sub 7418 df-neg 7419 df-reap 7812 df-ap 7819 df-div 7898 df-inn 8177 df-2 8235 df-3 8236 df-4 8237 df-n0 8426 df-z 8503 df-uz 8771 df-q 8856 df-rp 8886 df-fz 9176 df-fzo 9300 df-fl 9422 df-mod 9475 df-iseq 9592 df-iexp 9643 df-cj 9948 df-re 9949 df-im 9950 df-rsqrt 10103 df-abs 10104 df-dvds 10422 df-gcd 10564 df-lcm 10668

This theorem is referenced by: lcmgcdeq 10690

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