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Theorem dvdssq 15765

Description: Two numbers are divisible iff their squares are. (Contributed by Scott Fenton, 18-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)

**Assertion**
Ref	Expression
dvdssq	⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 ∥ 𝑁 ↔ (𝑀↑2) ∥ (𝑁↑2)))

**Proof of Theorem dvdssq**
Step	Hyp	Ref	Expression
1		breq1 4928	. . 3 ⊢ (𝑀 = 0 → (𝑀 ∥ 𝑁 ↔ 0 ∥ 𝑁))
2		sq0i 13369	. . . 4 ⊢ (𝑀 = 0 → (𝑀↑2) = 0)
3	2	breq1d 4935	. . 3 ⊢ (𝑀 = 0 → ((𝑀↑2) ∥ (𝑁↑2) ↔ 0 ∥ (𝑁↑2)))
4	1, 3	bibi12d 338	. 2 ⊢ (𝑀 = 0 → ((𝑀 ∥ 𝑁 ↔ (𝑀↑2) ∥ (𝑁↑2)) ↔ (0 ∥ 𝑁 ↔ 0 ∥ (𝑁↑2))))
5		nnabscl 14544	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → (abs‘𝑀) ∈ ℕ)
6		breq2 4929	. . . . . . 7 ⊢ (𝑁 = 0 → ((abs‘𝑀) ∥ 𝑁 ↔ (abs‘𝑀) ∥ 0))
7		sq0i 13369	. . . . . . . 8 ⊢ (𝑁 = 0 → (𝑁↑2) = 0)
8	7	breq2d 4937	. . . . . . 7 ⊢ (𝑁 = 0 → (((abs‘𝑀)↑2) ∥ (𝑁↑2) ↔ ((abs‘𝑀)↑2) ∥ 0))
9	6, 8	bibi12d 338	. . . . . 6 ⊢ (𝑁 = 0 → (((abs‘𝑀) ∥ 𝑁 ↔ ((abs‘𝑀)↑2) ∥ (𝑁↑2)) ↔ ((abs‘𝑀) ∥ 0 ↔ ((abs‘𝑀)↑2) ∥ 0)))
10		nnabscl 14544	. . . . . . . . 9 ⊢ ((𝑁 ∈ ℤ ∧ 𝑁 ≠ 0) → (abs‘𝑁) ∈ ℕ)
11		dvdssqlem 15764	. . . . . . . . 9 ⊢ (((abs‘𝑀) ∈ ℕ ∧ (abs‘𝑁) ∈ ℕ) → ((abs‘𝑀) ∥ (abs‘𝑁) ↔ ((abs‘𝑀)↑2) ∥ ((abs‘𝑁)↑2)))
12	10, 11	sylan2 584	. . . . . . . 8 ⊢ (((abs‘𝑀) ∈ ℕ ∧ (𝑁 ∈ ℤ ∧ 𝑁 ≠ 0)) → ((abs‘𝑀) ∥ (abs‘𝑁) ↔ ((abs‘𝑀)↑2) ∥ ((abs‘𝑁)↑2)))
13		nnz 11815	. . . . . . . . 9 ⊢ ((abs‘𝑀) ∈ ℕ → (abs‘𝑀) ∈ ℤ)
14		simpl 475	. . . . . . . . 9 ⊢ ((𝑁 ∈ ℤ ∧ 𝑁 ≠ 0) → 𝑁 ∈ ℤ)
15		dvdsabsb 15487	. . . . . . . . 9 ⊢ (((abs‘𝑀) ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((abs‘𝑀) ∥ 𝑁 ↔ (abs‘𝑀) ∥ (abs‘𝑁)))
16	13, 14, 15	syl2an 587	. . . . . . . 8 ⊢ (((abs‘𝑀) ∈ ℕ ∧ (𝑁 ∈ ℤ ∧ 𝑁 ≠ 0)) → ((abs‘𝑀) ∥ 𝑁 ↔ (abs‘𝑀) ∥ (abs‘𝑁)))
17		nnsqcl 13306	. . . . . . . . . . 11 ⊢ ((abs‘𝑀) ∈ ℕ → ((abs‘𝑀)↑2) ∈ ℕ)
18	17	nnzd 11897	. . . . . . . . . 10 ⊢ ((abs‘𝑀) ∈ ℕ → ((abs‘𝑀)↑2) ∈ ℤ)
19		zsqcl 13307	. . . . . . . . . . 11 ⊢ (𝑁 ∈ ℤ → (𝑁↑2) ∈ ℤ)
20	19	adantr 473	. . . . . . . . . 10 ⊢ ((𝑁 ∈ ℤ ∧ 𝑁 ≠ 0) → (𝑁↑2) ∈ ℤ)
21		dvdsabsb 15487	. . . . . . . . . 10 ⊢ ((((abs‘𝑀)↑2) ∈ ℤ ∧ (𝑁↑2) ∈ ℤ) → (((abs‘𝑀)↑2) ∥ (𝑁↑2) ↔ ((abs‘𝑀)↑2) ∥ (abs‘(𝑁↑2))))
22	18, 20, 21	syl2an 587	. . . . . . . . 9 ⊢ (((abs‘𝑀) ∈ ℕ ∧ (𝑁 ∈ ℤ ∧ 𝑁 ≠ 0)) → (((abs‘𝑀)↑2) ∥ (𝑁↑2) ↔ ((abs‘𝑀)↑2) ∥ (abs‘(𝑁↑2))))
23		zcn 11796	. . . . . . . . . . . . 13 ⊢ (𝑁 ∈ ℤ → 𝑁 ∈ ℂ)
24	23	adantr 473	. . . . . . . . . . . 12 ⊢ ((𝑁 ∈ ℤ ∧ 𝑁 ≠ 0) → 𝑁 ∈ ℂ)
25		abssq 14525	. . . . . . . . . . . 12 ⊢ (𝑁 ∈ ℂ → ((abs‘𝑁)↑2) = (abs‘(𝑁↑2)))
26	24, 25	syl 17	. . . . . . . . . . 11 ⊢ ((𝑁 ∈ ℤ ∧ 𝑁 ≠ 0) → ((abs‘𝑁)↑2) = (abs‘(𝑁↑2)))
27	26	breq2d 4937	. . . . . . . . . 10 ⊢ ((𝑁 ∈ ℤ ∧ 𝑁 ≠ 0) → (((abs‘𝑀)↑2) ∥ ((abs‘𝑁)↑2) ↔ ((abs‘𝑀)↑2) ∥ (abs‘(𝑁↑2))))
28	27	adantl 474	. . . . . . . . 9 ⊢ (((abs‘𝑀) ∈ ℕ ∧ (𝑁 ∈ ℤ ∧ 𝑁 ≠ 0)) → (((abs‘𝑀)↑2) ∥ ((abs‘𝑁)↑2) ↔ ((abs‘𝑀)↑2) ∥ (abs‘(𝑁↑2))))
29	22, 28	bitr4d 274	. . . . . . . 8 ⊢ (((abs‘𝑀) ∈ ℕ ∧ (𝑁 ∈ ℤ ∧ 𝑁 ≠ 0)) → (((abs‘𝑀)↑2) ∥ (𝑁↑2) ↔ ((abs‘𝑀)↑2) ∥ ((abs‘𝑁)↑2)))
30	12, 16, 29	3bitr4d 303	. . . . . . 7 ⊢ (((abs‘𝑀) ∈ ℕ ∧ (𝑁 ∈ ℤ ∧ 𝑁 ≠ 0)) → ((abs‘𝑀) ∥ 𝑁 ↔ ((abs‘𝑀)↑2) ∥ (𝑁↑2)))
31	30	anassrs 460	. . . . . 6 ⊢ ((((abs‘𝑀) ∈ ℕ ∧ 𝑁 ∈ ℤ) ∧ 𝑁 ≠ 0) → ((abs‘𝑀) ∥ 𝑁 ↔ ((abs‘𝑀)↑2) ∥ (𝑁↑2)))
32		dvds0 15483	. . . . . . . . 9 ⊢ ((abs‘𝑀) ∈ ℤ → (abs‘𝑀) ∥ 0)
33		zsqcl 13307	. . . . . . . . . 10 ⊢ ((abs‘𝑀) ∈ ℤ → ((abs‘𝑀)↑2) ∈ ℤ)
34		dvds0 15483	. . . . . . . . . 10 ⊢ (((abs‘𝑀)↑2) ∈ ℤ → ((abs‘𝑀)↑2) ∥ 0)
35	33, 34	syl 17	. . . . . . . . 9 ⊢ ((abs‘𝑀) ∈ ℤ → ((abs‘𝑀)↑2) ∥ 0)
36	32, 35	2thd 257	. . . . . . . 8 ⊢ ((abs‘𝑀) ∈ ℤ → ((abs‘𝑀) ∥ 0 ↔ ((abs‘𝑀)↑2) ∥ 0))
37	13, 36	syl 17	. . . . . . 7 ⊢ ((abs‘𝑀) ∈ ℕ → ((abs‘𝑀) ∥ 0 ↔ ((abs‘𝑀)↑2) ∥ 0))
38	37	adantr 473	. . . . . 6 ⊢ (((abs‘𝑀) ∈ ℕ ∧ 𝑁 ∈ ℤ) → ((abs‘𝑀) ∥ 0 ↔ ((abs‘𝑀)↑2) ∥ 0))
39	9, 31, 38	pm2.61ne 3046	. . . . 5 ⊢ (((abs‘𝑀) ∈ ℕ ∧ 𝑁 ∈ ℤ) → ((abs‘𝑀) ∥ 𝑁 ↔ ((abs‘𝑀)↑2) ∥ (𝑁↑2)))
40	5, 39	sylan 572	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) ∧ 𝑁 ∈ ℤ) → ((abs‘𝑀) ∥ 𝑁 ↔ ((abs‘𝑀)↑2) ∥ (𝑁↑2)))
41		absdvdsb 15486	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 ∥ 𝑁 ↔ (abs‘𝑀) ∥ 𝑁))
42	41	adantlr 703	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) ∧ 𝑁 ∈ ℤ) → (𝑀 ∥ 𝑁 ↔ (abs‘𝑀) ∥ 𝑁))
43		zsqcl 13307	. . . . . . 7 ⊢ (𝑀 ∈ ℤ → (𝑀↑2) ∈ ℤ)
44	43	adantr 473	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → (𝑀↑2) ∈ ℤ)
45		absdvdsb 15486	. . . . . 6 ⊢ (((𝑀↑2) ∈ ℤ ∧ (𝑁↑2) ∈ ℤ) → ((𝑀↑2) ∥ (𝑁↑2) ↔ (abs‘(𝑀↑2)) ∥ (𝑁↑2)))
46	44, 19, 45	syl2an 587	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) ∧ 𝑁 ∈ ℤ) → ((𝑀↑2) ∥ (𝑁↑2) ↔ (abs‘(𝑀↑2)) ∥ (𝑁↑2)))
47		zcn 11796	. . . . . . . . . 10 ⊢ (𝑀 ∈ ℤ → 𝑀 ∈ ℂ)
48		abssq 14525	. . . . . . . . . 10 ⊢ (𝑀 ∈ ℂ → ((abs‘𝑀)↑2) = (abs‘(𝑀↑2)))
49	47, 48	syl 17	. . . . . . . . 9 ⊢ (𝑀 ∈ ℤ → ((abs‘𝑀)↑2) = (abs‘(𝑀↑2)))
50	49	eqcomd 2777	. . . . . . . 8 ⊢ (𝑀 ∈ ℤ → (abs‘(𝑀↑2)) = ((abs‘𝑀)↑2))
51	50	adantr 473	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → (abs‘(𝑀↑2)) = ((abs‘𝑀)↑2))
52	51	breq1d 4935	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → ((abs‘(𝑀↑2)) ∥ (𝑁↑2) ↔ ((abs‘𝑀)↑2) ∥ (𝑁↑2)))
53	52	adantr 473	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) ∧ 𝑁 ∈ ℤ) → ((abs‘(𝑀↑2)) ∥ (𝑁↑2) ↔ ((abs‘𝑀)↑2) ∥ (𝑁↑2)))
54	46, 53	bitrd 271	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) ∧ 𝑁 ∈ ℤ) → ((𝑀↑2) ∥ (𝑁↑2) ↔ ((abs‘𝑀)↑2) ∥ (𝑁↑2)))
55	40, 42, 54	3bitr4d 303	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) ∧ 𝑁 ∈ ℤ) → (𝑀 ∥ 𝑁 ↔ (𝑀↑2) ∥ (𝑁↑2)))
56	55	an32s 640	. 2 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ 𝑀 ≠ 0) → (𝑀 ∥ 𝑁 ↔ (𝑀↑2) ∥ (𝑁↑2)))
57		0dvds 15488	. . . . 5 ⊢ (𝑁 ∈ ℤ → (0 ∥ 𝑁 ↔ 𝑁 = 0))
58		sqeq0 13299	. . . . . 6 ⊢ (𝑁 ∈ ℂ → ((𝑁↑2) = 0 ↔ 𝑁 = 0))
59	23, 58	syl 17	. . . . 5 ⊢ (𝑁 ∈ ℤ → ((𝑁↑2) = 0 ↔ 𝑁 = 0))
60	57, 59	bitr4d 274	. . . 4 ⊢ (𝑁 ∈ ℤ → (0 ∥ 𝑁 ↔ (𝑁↑2) = 0))
61		0dvds 15488	. . . . 5 ⊢ ((𝑁↑2) ∈ ℤ → (0 ∥ (𝑁↑2) ↔ (𝑁↑2) = 0))
62	19, 61	syl 17	. . . 4 ⊢ (𝑁 ∈ ℤ → (0 ∥ (𝑁↑2) ↔ (𝑁↑2) = 0))
63	60, 62	bitr4d 274	. . 3 ⊢ (𝑁 ∈ ℤ → (0 ∥ 𝑁 ↔ 0 ∥ (𝑁↑2)))
64	63	adantl 474	. 2 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (0 ∥ 𝑁 ↔ 0 ∥ (𝑁↑2)))
65	4, 56, 64	pm2.61ne 3046	1 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 ∥ 𝑁 ↔ (𝑀↑2) ∥ (𝑁↑2)))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 198 ∧ wa 387 = wceq 1508 ∈ wcel 2051 ≠ wne 2960 class class class wbr 4925 ‘cfv 6185 (class class class)co 6974 ℂcc 10331 0cc0 10333 ℕcn 11437 2c2 11493 ℤcz 11791 ↑cexp 13242 abscabs 14452 ∥ cdvds 15465

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1759 ax-4 1773 ax-5 1870 ax-6 1929 ax-7 1966 ax-8 2053 ax-9 2060 ax-10 2080 ax-11 2094 ax-12 2107 ax-13 2302 ax-ext 2743 ax-sep 5056 ax-nul 5063 ax-pow 5115 ax-pr 5182 ax-un 7277 ax-cnex 10389 ax-resscn 10390 ax-1cn 10391 ax-icn 10392 ax-addcl 10393 ax-addrcl 10394 ax-mulcl 10395 ax-mulrcl 10396 ax-mulcom 10397 ax-addass 10398 ax-mulass 10399 ax-distr 10400 ax-i2m1 10401 ax-1ne0 10402 ax-1rid 10403 ax-rnegex 10404 ax-rrecex 10405 ax-cnre 10406 ax-pre-lttri 10407 ax-pre-lttrn 10408 ax-pre-ltadd 10409 ax-pre-mulgt0 10410 ax-pre-sup 10411

This theorem depends on definitions: df-bi 199 df-an 388 df-or 835 df-3or 1070 df-3an 1071 df-tru 1511 df-ex 1744 df-nf 1748 df-sb 2017 df-mo 2548 df-eu 2585 df-clab 2752 df-cleq 2764 df-clel 2839 df-nfc 2911 df-ne 2961 df-nel 3067 df-ral 3086 df-rex 3087 df-reu 3088 df-rmo 3089 df-rab 3090 df-v 3410 df-sbc 3675 df-csb 3780 df-dif 3825 df-un 3827 df-in 3829 df-ss 3836 df-pss 3838 df-nul 4173 df-if 4345 df-pw 4418 df-sn 4436 df-pr 4438 df-tp 4440 df-op 4442 df-uni 4709 df-iun 4790 df-br 4926 df-opab 4988 df-mpt 5005 df-tr 5027 df-id 5308 df-eprel 5313 df-po 5322 df-so 5323 df-fr 5362 df-we 5364 df-xp 5409 df-rel 5410 df-cnv 5411 df-co 5412 df-dm 5413 df-rn 5414 df-res 5415 df-ima 5416 df-pred 5983 df-ord 6029 df-on 6030 df-lim 6031 df-suc 6032 df-iota 6149 df-fun 6187 df-fn 6188 df-f 6189 df-f1 6190 df-fo 6191 df-f1o 6192 df-fv 6193 df-riota 6935 df-ov 6977 df-oprab 6978 df-mpo 6979 df-om 7395 df-2nd 7500 df-wrecs 7748 df-recs 7810 df-rdg 7848 df-er 8087 df-en 8305 df-dom 8306 df-sdom 8307 df-sup 8699 df-inf 8700 df-pnf 10474 df-mnf 10475 df-xr 10476 df-ltxr 10477 df-le 10478 df-sub 10670 df-neg 10671 df-div 11097 df-nn 11438 df-2 11501 df-3 11502 df-n0 11706 df-z 11792 df-uz 12057 df-rp 12203 df-fl 12975 df-mod 13051 df-seq 13183 df-exp 13243 df-cj 14317 df-re 14318 df-im 14319 df-sqrt 14453 df-abs 14454 df-dvds 15466 df-gcd 15702

This theorem is referenced by: pythagtriplem19 16024 4sqlem9 16136 4sqlem10 16137 lgsdir 25625 2sqlem8a 25718

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