gcdneg - Intuitionistic Logic Explorer

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Theorem gcdneg 12742

Description: Negating one operand of the gcd operator does not alter the result. (Contributed by Paul Chapman, 21-Mar-2011.)

**Assertion**
Ref	Expression
gcdneg	⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd -𝑁) = (𝑀 gcd 𝑁))

**Proof of Theorem gcdneg**
Step	Hyp	Ref	Expression
1		oveq12 6088	. . . . 5 ⊢ ((𝑀 = 0 ∧ 𝑁 = 0) → (𝑀 gcd 𝑁) = (0 gcd 0))
2	1	adantl 277	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 = 0 ∧ 𝑁 = 0)) → (𝑀 gcd 𝑁) = (0 gcd 0))
3		zcn 9632	. . . . . . . . 9 ⊢ (𝑁 ∈ ℤ → 𝑁 ∈ ℂ)
4	3	negeq0d 8623	. . . . . . . 8 ⊢ (𝑁 ∈ ℤ → (𝑁 = 0 ↔ -𝑁 = 0))
5	4	anbi2d 468	. . . . . . 7 ⊢ (𝑁 ∈ ℤ → ((𝑀 = 0 ∧ 𝑁 = 0) ↔ (𝑀 = 0 ∧ -𝑁 = 0)))
6	5	adantl 277	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 = 0 ∧ 𝑁 = 0) ↔ (𝑀 = 0 ∧ -𝑁 = 0)))
7		oveq12 6088	. . . . . 6 ⊢ ((𝑀 = 0 ∧ -𝑁 = 0) → (𝑀 gcd -𝑁) = (0 gcd 0))
8	6, 7	biimtrdi 163	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 = 0 ∧ 𝑁 = 0) → (𝑀 gcd -𝑁) = (0 gcd 0)))
9	8	imp 124	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 = 0 ∧ 𝑁 = 0)) → (𝑀 gcd -𝑁) = (0 gcd 0))
10	2, 9	eqtr4d 2274	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 = 0 ∧ 𝑁 = 0)) → (𝑀 gcd 𝑁) = (𝑀 gcd -𝑁))
11		gcddvds 12723	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ 𝑁))
12		gcdcl 12726	. . . . . . . . . 10 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) ∈ ℕ₀)
13	12	nn0zd 9749	. . . . . . . . 9 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) ∈ ℤ)
14		dvdsnegb 12558	. . . . . . . . 9 ⊢ (((𝑀 gcd 𝑁) ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd 𝑁) ∥ 𝑁 ↔ (𝑀 gcd 𝑁) ∥ -𝑁))
15	13, 14	sylancom 424	. . . . . . . 8 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd 𝑁) ∥ 𝑁 ↔ (𝑀 gcd 𝑁) ∥ -𝑁))
16	15	anbi2d 468	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ 𝑁) ↔ ((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ -𝑁)))
17	11, 16	mpbid 147	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ -𝑁))
18	6	notbid 677	. . . . . . . 8 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (¬ (𝑀 = 0 ∧ 𝑁 = 0) ↔ ¬ (𝑀 = 0 ∧ -𝑁 = 0)))
19		simpl 109	. . . . . . . . 9 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → 𝑀 ∈ ℤ)
20		znegcl 9658	. . . . . . . . . 10 ⊢ (𝑁 ∈ ℤ → -𝑁 ∈ ℤ)
21	20	adantl 277	. . . . . . . . 9 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → -𝑁 ∈ ℤ)
22		dvdslegcd 12724	. . . . . . . . . 10 ⊢ ((((𝑀 gcd 𝑁) ∈ ℤ ∧ 𝑀 ∈ ℤ ∧ -𝑁 ∈ ℤ) ∧ ¬ (𝑀 = 0 ∧ -𝑁 = 0)) → (((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ -𝑁) → (𝑀 gcd 𝑁) ≤ (𝑀 gcd -𝑁)))
23	22	ex 115	. . . . . . . . 9 ⊢ (((𝑀 gcd 𝑁) ∈ ℤ ∧ 𝑀 ∈ ℤ ∧ -𝑁 ∈ ℤ) → (¬ (𝑀 = 0 ∧ -𝑁 = 0) → (((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ -𝑁) → (𝑀 gcd 𝑁) ≤ (𝑀 gcd -𝑁))))
24	13, 19, 21, 23	syl3anc 1278	. . . . . . . 8 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (¬ (𝑀 = 0 ∧ -𝑁 = 0) → (((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ -𝑁) → (𝑀 gcd 𝑁) ≤ (𝑀 gcd -𝑁))))
25	18, 24	sylbid 150	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (¬ (𝑀 = 0 ∧ 𝑁 = 0) → (((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ -𝑁) → (𝑀 gcd 𝑁) ≤ (𝑀 gcd -𝑁))))
26	25	com12 30	. . . . . 6 ⊢ (¬ (𝑀 = 0 ∧ 𝑁 = 0) → ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (((𝑀 gcd 𝑁) ∥ 𝑀 ∧ (𝑀 gcd 𝑁) ∥ -𝑁) → (𝑀 gcd 𝑁) ≤ (𝑀 gcd -𝑁))))
27	17, 26	mpdi 43	. . . . 5 ⊢ (¬ (𝑀 = 0 ∧ 𝑁 = 0) → ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) ≤ (𝑀 gcd -𝑁)))
28	27	impcom 125	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬ (𝑀 = 0 ∧ 𝑁 = 0)) → (𝑀 gcd 𝑁) ≤ (𝑀 gcd -𝑁))
29		gcddvds 12723	. . . . . . . 8 ⊢ ((𝑀 ∈ ℤ ∧ -𝑁 ∈ ℤ) → ((𝑀 gcd -𝑁) ∥ 𝑀 ∧ (𝑀 gcd -𝑁) ∥ -𝑁))
30	20, 29	sylan2 286	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd -𝑁) ∥ 𝑀 ∧ (𝑀 gcd -𝑁) ∥ -𝑁))
31		gcdcl 12726	. . . . . . . . . . 11 ⊢ ((𝑀 ∈ ℤ ∧ -𝑁 ∈ ℤ) → (𝑀 gcd -𝑁) ∈ ℕ₀)
32	31	nn0zd 9749	. . . . . . . . . 10 ⊢ ((𝑀 ∈ ℤ ∧ -𝑁 ∈ ℤ) → (𝑀 gcd -𝑁) ∈ ℤ)
33	20, 32	sylan2 286	. . . . . . . . 9 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd -𝑁) ∈ ℤ)
34		dvdsnegb 12558	. . . . . . . . 9 ⊢ (((𝑀 gcd -𝑁) ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd -𝑁) ∥ 𝑁 ↔ (𝑀 gcd -𝑁) ∥ -𝑁))
35	33, 34	sylancom 424	. . . . . . . 8 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd -𝑁) ∥ 𝑁 ↔ (𝑀 gcd -𝑁) ∥ -𝑁))
36	35	anbi2d 468	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (((𝑀 gcd -𝑁) ∥ 𝑀 ∧ (𝑀 gcd -𝑁) ∥ 𝑁) ↔ ((𝑀 gcd -𝑁) ∥ 𝑀 ∧ (𝑀 gcd -𝑁) ∥ -𝑁)))
37	30, 36	mpbird 167	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd -𝑁) ∥ 𝑀 ∧ (𝑀 gcd -𝑁) ∥ 𝑁))
38		simpr 110	. . . . . . . 8 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → 𝑁 ∈ ℤ)
39		dvdslegcd 12724	. . . . . . . . 9 ⊢ ((((𝑀 gcd -𝑁) ∈ ℤ ∧ 𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬ (𝑀 = 0 ∧ 𝑁 = 0)) → (((𝑀 gcd -𝑁) ∥ 𝑀 ∧ (𝑀 gcd -𝑁) ∥ 𝑁) → (𝑀 gcd -𝑁) ≤ (𝑀 gcd 𝑁)))
40	39	ex 115	. . . . . . . 8 ⊢ (((𝑀 gcd -𝑁) ∈ ℤ ∧ 𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (¬ (𝑀 = 0 ∧ 𝑁 = 0) → (((𝑀 gcd -𝑁) ∥ 𝑀 ∧ (𝑀 gcd -𝑁) ∥ 𝑁) → (𝑀 gcd -𝑁) ≤ (𝑀 gcd 𝑁))))
41	33, 19, 38, 40	syl3anc 1278	. . . . . . 7 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (¬ (𝑀 = 0 ∧ 𝑁 = 0) → (((𝑀 gcd -𝑁) ∥ 𝑀 ∧ (𝑀 gcd -𝑁) ∥ 𝑁) → (𝑀 gcd -𝑁) ≤ (𝑀 gcd 𝑁))))
42	41	com12 30	. . . . . 6 ⊢ (¬ (𝑀 = 0 ∧ 𝑁 = 0) → ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (((𝑀 gcd -𝑁) ∥ 𝑀 ∧ (𝑀 gcd -𝑁) ∥ 𝑁) → (𝑀 gcd -𝑁) ≤ (𝑀 gcd 𝑁))))
43	37, 42	mpdi 43	. . . . 5 ⊢ (¬ (𝑀 = 0 ∧ 𝑁 = 0) → ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd -𝑁) ≤ (𝑀 gcd 𝑁)))
44	43	impcom 125	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬ (𝑀 = 0 ∧ 𝑁 = 0)) → (𝑀 gcd -𝑁) ≤ (𝑀 gcd 𝑁))
45	13	zred 9751	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) ∈ ℝ)
46	33	zred 9751	. . . . . 6 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd -𝑁) ∈ ℝ)
47	45, 46	letri3d 8435	. . . . 5 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 gcd 𝑁) = (𝑀 gcd -𝑁) ↔ ((𝑀 gcd 𝑁) ≤ (𝑀 gcd -𝑁) ∧ (𝑀 gcd -𝑁) ≤ (𝑀 gcd 𝑁))))
48	47	adantr 276	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬ (𝑀 = 0 ∧ 𝑁 = 0)) → ((𝑀 gcd 𝑁) = (𝑀 gcd -𝑁) ↔ ((𝑀 gcd 𝑁) ≤ (𝑀 gcd -𝑁) ∧ (𝑀 gcd -𝑁) ≤ (𝑀 gcd 𝑁))))
49	28, 44, 48	mpbir2and 957	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬ (𝑀 = 0 ∧ 𝑁 = 0)) → (𝑀 gcd 𝑁) = (𝑀 gcd -𝑁))
50		gcdmndc 12715	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → DECID (𝑀 = 0 ∧ 𝑁 = 0))
51		exmiddc 848	. . . 4 ⊢ (DECID (𝑀 = 0 ∧ 𝑁 = 0) → ((𝑀 = 0 ∧ 𝑁 = 0) ∨ ¬ (𝑀 = 0 ∧ 𝑁 = 0)))
52	50, 51	syl 14	. . 3 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → ((𝑀 = 0 ∧ 𝑁 = 0) ∨ ¬ (𝑀 = 0 ∧ 𝑁 = 0)))
53	10, 49, 52	mpjaodan 810	. 2 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd 𝑁) = (𝑀 gcd -𝑁))
54	53	eqcomd 2244	1 ⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 gcd -𝑁) = (𝑀 gcd 𝑁))

Colors of variables: wff set class

Syntax hints: ¬ wn 3 → wi 4 ∧ wa 104 ↔ wb 105 ∨ wo 720 DECID wdc 846 ∧ w3a 1009 = wceq 1402 ∈ wcel 2209 class class class wbr 4128 (class class class)co 6079 0cc0 8173 ≤ cle 8355 -cneg 8492 ℤcz 9627 ∥ cdvds 12537 gcd cgcd 12713

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 623 ax-in2 624 ax-io 721 ax-5 1500 ax-7 1501 ax-gen 1502 ax-ie1 1546 ax-ie2 1547 ax-8 1557 ax-10 1558 ax-11 1559 ax-i12 1560 ax-bndl 1562 ax-4 1563 ax-17 1579 ax-i9 1583 ax-ial 1587 ax-i5r 1588 ax-14 2212 ax-ext 2220 ax-coll 4244 ax-sep 4247 ax-nul 4257 ax-pow 4309 ax-pr 4344 ax-un 4576 ax-setind 4682 ax-iinf 4733 ax-cnex 8264 ax-resscn 8265 ax-1cn 8266 ax-1re 8267 ax-icn 8268 ax-addcl 8269 ax-addrcl 8270 ax-mulcl 8271 ax-mulrcl 8272 ax-addcom 8273 ax-mulcom 8274 ax-addass 8275 ax-mulass 8276 ax-distr 8277 ax-i2m1 8278 ax-0lt1 8279 ax-1rid 8280 ax-0id 8281 ax-rnegex 8282 ax-precex 8283 ax-cnre 8284 ax-pre-ltirr 8285 ax-pre-ltwlin 8286 ax-pre-lttrn 8287 ax-pre-apti 8288 ax-pre-ltadd 8289 ax-pre-mulgt0 8290 ax-pre-mulext 8291 ax-arch 8292 ax-caucvg 8293

This theorem depends on definitions: df-bi 117 df-dc 847 df-3or 1010 df-3an 1011 df-tru 1405 df-fal 1408 df-nf 1514 df-sb 1816 df-eu 2089 df-mo 2090 df-clab 2225 df-cleq 2231 df-clel 2234 df-nfc 2381 df-ne 2421 df-nel 2516 df-ral 2533 df-rex 2534 df-reu 2535 df-rmo 2536 df-rab 2537 df-v 2823 df-sbc 3052 df-csb 3148 df-dif 3222 df-un 3224 df-in 3226 df-ss 3233 df-nul 3521 df-if 3639 df-pw 3690 df-sn 3714 df-pr 3715 df-op 3717 df-uni 3934 df-int 3969 df-iun 4012 df-br 4129 df-opab 4191 df-mpt 4192 df-tr 4228 df-id 4436 df-po 4439 df-iso 4440 df-iord 4509 df-on 4511 df-ilim 4512 df-suc 4514 df-iom 4736 df-xp 4778 df-rel 4779 df-cnv 4780 df-co 4781 df-dm 4782 df-rn 4783 df-res 4784 df-ima 4785 df-iota 5335 df-fun 5377 df-fn 5378 df-f 5379 df-f1 5380 df-fo 5381 df-f1o 5382 df-fv 5383 df-riota 6032 df-ov 6082 df-oprab 6083 df-mpo 6084 df-1st 6368 df-2nd 6369 df-recs 6570 df-frec 6656 df-sup 7318 df-pnf 8356 df-mnf 8357 df-xr 8358 df-ltxr 8359 df-le 8360 df-sub 8493 df-neg 8494 df-reap 8897 df-ap 8904 df-div 8997 df-inn 9288 df-2 9346 df-3 9347 df-4 9348 df-n0 9547 df-z 9628 df-uz 9905 df-q 10003 df-rp 10038 df-fz 10395 df-fzo 10533 df-fl 10688 df-mod 10743 df-seqfrec 10868 df-exp 10959 df-cj 11590 df-re 11591 df-im 11592 df-rsqrt 11747 df-abs 11748 df-dvds 12538 df-gcd 12714

This theorem is referenced by: neggcd 12743 gcdabs 12748

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