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Theorem lcmgcdeq 16523

Description: Two integers' absolute values are equal iff their least common multiple and greatest common divisor are equal. (Contributed by Steve Rodriguez, 20-Jan-2020.)

**Assertion**
Ref	Expression
lcmgcdeq	⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 lcm 𝑁) = (𝑀 gcd 𝑁) ↔ (abs‘𝑀) = (abs‘𝑁)))

**Proof of Theorem lcmgcdeq**
Step	Hyp	Ref	Expression
1		dvdslcm 16509	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 ∥ (𝑀 lcm 𝑁) ∧ 𝑁 ∥ (𝑀 lcm 𝑁)))
2	1	simpld 494	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → 𝑀 ∥ (𝑀 lcm 𝑁))
3	2	adantr 480	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → 𝑀 ∥ (𝑀 lcm 𝑁))
4		gcddvds 16414	. . . . . . . 8 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ 𝑁))
5	4	simprd 495	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) ∥ 𝑁)
6		breq1 5095	. . . . . . 7 ⊢ ((𝑀 lcm 𝑁) = (𝑀 gcd 𝑁) → ((𝑀 lcm 𝑁) ∥ 𝑁 ↔ (𝑀 gcd 𝑁) ∥ 𝑁))
7	5, 6	syl5ibrcom 247	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 lcm 𝑁) = (𝑀 gcd 𝑁) → (𝑀 lcm 𝑁) ∥ 𝑁))
8	7	imp 406	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → (𝑀 lcm 𝑁) ∥ 𝑁)
9		lcmcl 16512	. . . . . . . . . . 11 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 lcm 𝑁) ∈ ℕ₀)
10	9	nn0zd 12497	. . . . . . . . . 10 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 lcm 𝑁) ∈ ℤ)
11		dvdstr 16205	. . . . . . . . . 10 ⊢ ((𝑀 ∈ ℤ ∧ (𝑀 lcm 𝑁) ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑁) → 𝑀 ∥ 𝑁))
12	10, 11	syl3an2 1164	. . . . . . . . 9 ⊢ ((𝑀 ∈ ℤ ∧ (𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ 𝑁 ∈ ℤ) → ((𝑀 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑁) → 𝑀 ∥ 𝑁))
13	12	3com12 1123	. . . . . . . 8 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ 𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑁) → 𝑀 ∥ 𝑁))
14	13	3expb 1120	. . . . . . 7 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ)) → ((𝑀 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑁) → 𝑀 ∥ 𝑁))
15	14	anidms 566	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑁) → 𝑀 ∥ 𝑁))
16	15	adantr 480	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → ((𝑀 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑁) → 𝑀 ∥ 𝑁))
17	3, 8, 16	mp2and 699	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → 𝑀 ∥ 𝑁)
18		absdvdsb 16185	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 ∥ 𝑁 ↔ (abs‘𝑀) ∥ 𝑁))
19		zabscl 15220	. . . . . . 7 ⊢ (𝑀 ∈ ℤ → (abs‘𝑀) ∈ ℤ)
20		dvdsabsb 16186	. . . . . . 7 ⊢ (((abs‘𝑀) ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((abs‘𝑀) ∥ 𝑁 ↔ (abs‘𝑀) ∥ (abs‘𝑁)))
21	19, 20	sylan 580	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((abs‘𝑀) ∥ 𝑁 ↔ (abs‘𝑀) ∥ (abs‘𝑁)))
22	18, 21	bitrd 279	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 ∥ 𝑁 ↔ (abs‘𝑀) ∥ (abs‘𝑁)))
23	22	adantr 480	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → (𝑀 ∥ 𝑁 ↔ (abs‘𝑀) ∥ (abs‘𝑁)))
24	17, 23	mpbid 232	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → (abs‘𝑀) ∥ (abs‘𝑁))
25	1	simprd 495	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → 𝑁 ∥ (𝑀 lcm 𝑁))
26	25	adantr 480	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → 𝑁 ∥ (𝑀 lcm 𝑁))
27	4	simpld 494	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) ∥ 𝑀)
28		breq1 5095	. . . . . . 7 ⊢ ((𝑀 lcm 𝑁) = (𝑀 gcd 𝑁) → ((𝑀 lcm 𝑁) ∥ 𝑀 ↔ (𝑀 gcd 𝑁) ∥ 𝑀))
29	27, 28	syl5ibrcom 247	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 lcm 𝑁) = (𝑀 gcd 𝑁) → (𝑀 lcm 𝑁) ∥ 𝑀))
30	29	imp 406	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → (𝑀 lcm 𝑁) ∥ 𝑀)
31		dvdstr 16205	. . . . . . . . . 10 ⊢ ((𝑁 ∈ ℤ ∧ (𝑀 lcm 𝑁) ∈ ℤ ∧ 𝑀 ∈ ℤ) → ((𝑁 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑀) → 𝑁 ∥ 𝑀))
32	10, 31	syl3an2 1164	. . . . . . . . 9 ⊢ ((𝑁 ∈ ℤ ∧ (𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ 𝑀 ∈ ℤ) → ((𝑁 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑀) → 𝑁 ∥ 𝑀))
33	32	3coml 1127	. . . . . . . 8 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ 𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑁 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑀) → 𝑁 ∥ 𝑀))
34	33	3expb 1120	. . . . . . 7 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ)) → ((𝑁 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑀) → 𝑁 ∥ 𝑀))
35	34	anidms 566	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑁 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑀) → 𝑁 ∥ 𝑀))
36	35	adantr 480	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → ((𝑁 ∥ (𝑀 lcm 𝑁) ∧ (𝑀 lcm 𝑁) ∥ 𝑀) → 𝑁 ∥ 𝑀))
37	26, 30, 36	mp2and 699	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → 𝑁 ∥ 𝑀)
38		absdvdsb 16185	. . . . . . 7 ⊢ ((𝑁 ∈ ℤ ∧ 𝑀 ∈ ℤ) → (𝑁 ∥ 𝑀 ↔ (abs‘𝑁) ∥ 𝑀))
39		zabscl 15220	. . . . . . . 8 ⊢ (𝑁 ∈ ℤ → (abs‘𝑁) ∈ ℤ)
40		dvdsabsb 16186	. . . . . . . 8 ⊢ (((abs‘𝑁) ∈ ℤ ∧ 𝑀 ∈ ℤ) → ((abs‘𝑁) ∥ 𝑀 ↔ (abs‘𝑁) ∥ (abs‘𝑀)))
41	39, 40	sylan 580	. . . . . . 7 ⊢ ((𝑁 ∈ ℤ ∧ 𝑀 ∈ ℤ) → ((abs‘𝑁) ∥ 𝑀 ↔ (abs‘𝑁) ∥ (abs‘𝑀)))
42	38, 41	bitrd 279	. . . . . 6 ⊢ ((𝑁 ∈ ℤ ∧ 𝑀 ∈ ℤ) → (𝑁 ∥ 𝑀 ↔ (abs‘𝑁) ∥ (abs‘𝑀)))
43	42	ancoms 458	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑁 ∥ 𝑀 ↔ (abs‘𝑁) ∥ (abs‘𝑀)))
44	43	adantr 480	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → (𝑁 ∥ 𝑀 ↔ (abs‘𝑁) ∥ (abs‘𝑀)))
45	37, 44	mpbid 232	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → (abs‘𝑁) ∥ (abs‘𝑀))
46		nn0abscl 15219	. . . . . . 7 ⊢ (𝑀 ∈ ℤ → (abs‘𝑀) ∈ ℕ₀)
47		nn0abscl 15219	. . . . . . 7 ⊢ (𝑁 ∈ ℤ → (abs‘𝑁) ∈ ℕ₀)
48	46, 47	anim12i 613	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((abs‘𝑀) ∈ ℕ₀ ∧ (abs‘𝑁) ∈ ℕ₀))
49		dvdseq 16225	. . . . . 6 ⊢ ((((abs‘𝑀) ∈ ℕ₀ ∧ (abs‘𝑁) ∈ ℕ₀) ∧ ((abs‘𝑀) ∥ (abs‘𝑁) ∧ (abs‘𝑁) ∥ (abs‘𝑀))) → (abs‘𝑀) = (abs‘𝑁))
50	48, 49	sylan 580	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ((abs‘𝑀) ∥ (abs‘𝑁) ∧ (abs‘𝑁) ∥ (abs‘𝑀))) → (abs‘𝑀) = (abs‘𝑁))
51	50	ex 412	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (((abs‘𝑀) ∥ (abs‘𝑁) ∧ (abs‘𝑁) ∥ (abs‘𝑀)) → (abs‘𝑀) = (abs‘𝑁)))
52	51	adantr 480	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → (((abs‘𝑀) ∥ (abs‘𝑁) ∧ (abs‘𝑁) ∥ (abs‘𝑀)) → (abs‘𝑀) = (abs‘𝑁)))
53	24, 45, 52	mp2and 699	. 2 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)) → (abs‘𝑀) = (abs‘𝑁))
54		lcmid 16520	. . . . . . . 8 ⊢ ((abs‘𝑀) ∈ ℤ → ((abs‘𝑀) lcm (abs‘𝑀)) = (abs‘(abs‘𝑀)))
55	19, 54	syl 17	. . . . . . 7 ⊢ (𝑀 ∈ ℤ → ((abs‘𝑀) lcm (abs‘𝑀)) = (abs‘(abs‘𝑀)))
56		gcdid 16438	. . . . . . . 8 ⊢ ((abs‘𝑀) ∈ ℤ → ((abs‘𝑀) gcd (abs‘𝑀)) = (abs‘(abs‘𝑀)))
57	19, 56	syl 17	. . . . . . 7 ⊢ (𝑀 ∈ ℤ → ((abs‘𝑀) gcd (abs‘𝑀)) = (abs‘(abs‘𝑀)))
58	55, 57	eqtr4d 2767	. . . . . 6 ⊢ (𝑀 ∈ ℤ → ((abs‘𝑀) lcm (abs‘𝑀)) = ((abs‘𝑀) gcd (abs‘𝑀)))
59		oveq2 7357	. . . . . . 7 ⊢ ((abs‘𝑀) = (abs‘𝑁) → ((abs‘𝑀) lcm (abs‘𝑀)) = ((abs‘𝑀) lcm (abs‘𝑁)))
60		oveq2 7357	. . . . . . 7 ⊢ ((abs‘𝑀) = (abs‘𝑁) → ((abs‘𝑀) gcd (abs‘𝑀)) = ((abs‘𝑀) gcd (abs‘𝑁)))
61	59, 60	eqeq12d 2745	. . . . . 6 ⊢ ((abs‘𝑀) = (abs‘𝑁) → (((abs‘𝑀) lcm (abs‘𝑀)) = ((abs‘𝑀) gcd (abs‘𝑀)) ↔ ((abs‘𝑀) lcm (abs‘𝑁)) = ((abs‘𝑀) gcd (abs‘𝑁))))
62	58, 61	syl5ibcom 245	. . . . 5 ⊢ (𝑀 ∈ ℤ → ((abs‘𝑀) = (abs‘𝑁) → ((abs‘𝑀) lcm (abs‘𝑁)) = ((abs‘𝑀) gcd (abs‘𝑁))))
63	62	imp 406	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ (abs‘𝑀) = (abs‘𝑁)) → ((abs‘𝑀) lcm (abs‘𝑁)) = ((abs‘𝑀) gcd (abs‘𝑁)))
64	63	adantlr 715	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (abs‘𝑀) = (abs‘𝑁)) → ((abs‘𝑀) lcm (abs‘𝑁)) = ((abs‘𝑀) gcd (abs‘𝑁)))
65		lcmabs 16516	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((abs‘𝑀) lcm (abs‘𝑁)) = (𝑀 lcm 𝑁))
66		gcdabs 16442	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((abs‘𝑀) gcd (abs‘𝑁)) = (𝑀 gcd 𝑁))
67	65, 66	eqeq12d 2745	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (((abs‘𝑀) lcm (abs‘𝑁)) = ((abs‘𝑀) gcd (abs‘𝑁)) ↔ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)))
68	67	adantr 480	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (abs‘𝑀) = (abs‘𝑁)) → (((abs‘𝑀) lcm (abs‘𝑁)) = ((abs‘𝑀) gcd (abs‘𝑁)) ↔ (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁)))
69	64, 68	mpbid 232	. 2 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (abs‘𝑀) = (abs‘𝑁)) → (𝑀 lcm 𝑁) = (𝑀 gcd 𝑁))
70	53, 69	impbida 800	1 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 lcm 𝑁) = (𝑀 gcd 𝑁) ↔ (abs‘𝑀) = (abs‘𝑁)))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 206 ∧ wa 395 = wceq 1540 ∈ wcel 2109 class class class wbr 5092 ‘cfv 6482 (class class class)co 7349 ℕ₀cn0 12384 ℤcz 12471 abscabs 15141 ∥ cdvds 16163 gcd cgcd 16405 lcm clcm 16499

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1967 ax-7 2008 ax-8 2111 ax-9 2119 ax-10 2142 ax-11 2158 ax-12 2178 ax-ext 2701 ax-sep 5235 ax-nul 5245 ax-pow 5304 ax-pr 5371 ax-un 7671 ax-cnex 11065 ax-resscn 11066 ax-1cn 11067 ax-icn 11068 ax-addcl 11069 ax-addrcl 11070 ax-mulcl 11071 ax-mulrcl 11072 ax-mulcom 11073 ax-addass 11074 ax-mulass 11075 ax-distr 11076 ax-i2m1 11077 ax-1ne0 11078 ax-1rid 11079 ax-rnegex 11080 ax-rrecex 11081 ax-cnre 11082 ax-pre-lttri 11083 ax-pre-lttrn 11084 ax-pre-ltadd 11085 ax-pre-mulgt0 11086 ax-pre-sup 11087

This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1543 df-fal 1553 df-ex 1780 df-nf 1784 df-sb 2066 df-mo 2533 df-eu 2562 df-clab 2708 df-cleq 2721 df-clel 2803 df-nfc 2878 df-ne 2926 df-nel 3030 df-ral 3045 df-rex 3054 df-rmo 3343 df-reu 3344 df-rab 3395 df-v 3438 df-sbc 3743 df-csb 3852 df-dif 3906 df-un 3908 df-in 3910 df-ss 3920 df-pss 3923 df-nul 4285 df-if 4477 df-pw 4553 df-sn 4578 df-pr 4580 df-op 4584 df-uni 4859 df-iun 4943 df-br 5093 df-opab 5155 df-mpt 5174 df-tr 5200 df-id 5514 df-eprel 5519 df-po 5527 df-so 5528 df-fr 5572 df-we 5574 df-xp 5625 df-rel 5626 df-cnv 5627 df-co 5628 df-dm 5629 df-rn 5630 df-res 5631 df-ima 5632 df-pred 6249 df-ord 6310 df-on 6311 df-lim 6312 df-suc 6313 df-iota 6438 df-fun 6484 df-fn 6485 df-f 6486 df-f1 6487 df-fo 6488 df-f1o 6489 df-fv 6490 df-riota 7306 df-ov 7352 df-oprab 7353 df-mpo 7354 df-om 7800 df-2nd 7925 df-frecs 8214 df-wrecs 8245 df-recs 8294 df-rdg 8332 df-er 8625 df-en 8873 df-dom 8874 df-sdom 8875 df-sup 9332 df-inf 9333 df-pnf 11151 df-mnf 11152 df-xr 11153 df-ltxr 11154 df-le 11155 df-sub 11349 df-neg 11350 df-div 11778 df-nn 12129 df-2 12191 df-3 12192 df-n0 12385 df-z 12472 df-uz 12736 df-rp 12894 df-fl 13696 df-mod 13774 df-seq 13909 df-exp 13969 df-cj 15006 df-re 15007 df-im 15008 df-sqrt 15142 df-abs 15143 df-dvds 16164 df-gcd 16406 df-lcm 16501

This theorem is referenced by: (None)

W3C validator