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Theorem 2sq 27381

Description: All primes of the form 4𝑘 + 1 are sums of two squares. This is Metamath 100 proof #20. (Contributed by Mario Carneiro, 20-Jun-2015.)

**Assertion**
Ref	Expression
2sq	⊢ ((𝑃 ∈ ℙ ∧ (𝑃 mod 4) = 1) → ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ 𝑃 = ((𝑥↑2) + (𝑦↑2)))

Distinct variable group: 𝑥,𝑦,𝑃

Proof of Theorem 2sq Dummy variables 𝑎 𝑏 𝑤 𝑧 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		eqid 2725	. . 3 ⊢ ran (𝑤 ∈ ℤ[i] ↦ ((abs‘𝑤)↑2)) = ran (𝑤 ∈ ℤ[i] ↦ ((abs‘𝑤)↑2))
2		oveq1 7423	. . . . . . 7 ⊢ (𝑎 = 𝑥 → (𝑎 gcd 𝑏) = (𝑥 gcd 𝑏))
3	2	eqeq1d 2727	. . . . . 6 ⊢ (𝑎 = 𝑥 → ((𝑎 gcd 𝑏) = 1 ↔ (𝑥 gcd 𝑏) = 1))
4		oveq1 7423	. . . . . . . 8 ⊢ (𝑎 = 𝑥 → (𝑎↑2) = (𝑥↑2))
5	4	oveq1d 7431	. . . . . . 7 ⊢ (𝑎 = 𝑥 → ((𝑎↑2) + (𝑏↑2)) = ((𝑥↑2) + (𝑏↑2)))
6	5	eqeq2d 2736	. . . . . 6 ⊢ (𝑎 = 𝑥 → (𝑧 = ((𝑎↑2) + (𝑏↑2)) ↔ 𝑧 = ((𝑥↑2) + (𝑏↑2))))
7	3, 6	anbi12d 630	. . . . 5 ⊢ (𝑎 = 𝑥 → (((𝑎 gcd 𝑏) = 1 ∧ 𝑧 = ((𝑎↑2) + (𝑏↑2))) ↔ ((𝑥 gcd 𝑏) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑏↑2)))))
8		oveq2 7424	. . . . . . 7 ⊢ (𝑏 = 𝑦 → (𝑥 gcd 𝑏) = (𝑥 gcd 𝑦))
9	8	eqeq1d 2727	. . . . . 6 ⊢ (𝑏 = 𝑦 → ((𝑥 gcd 𝑏) = 1 ↔ (𝑥 gcd 𝑦) = 1))
10		oveq1 7423	. . . . . . . 8 ⊢ (𝑏 = 𝑦 → (𝑏↑2) = (𝑦↑2))
11	10	oveq2d 7432	. . . . . . 7 ⊢ (𝑏 = 𝑦 → ((𝑥↑2) + (𝑏↑2)) = ((𝑥↑2) + (𝑦↑2)))
12	11	eqeq2d 2736	. . . . . 6 ⊢ (𝑏 = 𝑦 → (𝑧 = ((𝑥↑2) + (𝑏↑2)) ↔ 𝑧 = ((𝑥↑2) + (𝑦↑2))))
13	9, 12	anbi12d 630	. . . . 5 ⊢ (𝑏 = 𝑦 → (((𝑥 gcd 𝑏) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑏↑2))) ↔ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2)))))
14	7, 13	cbvrex2vw 3230	. . . 4 ⊢ (∃𝑎 ∈ ℤ ∃𝑏 ∈ ℤ ((𝑎 gcd 𝑏) = 1 ∧ 𝑧 = ((𝑎↑2) + (𝑏↑2))) ↔ ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2))))
15	14	abbii 2795	. . 3 ⊢ {𝑧 ∣ ∃𝑎 ∈ ℤ ∃𝑏 ∈ ℤ ((𝑎 gcd 𝑏) = 1 ∧ 𝑧 = ((𝑎↑2) + (𝑏↑2)))} = {𝑧 ∣ ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ ((𝑥 gcd 𝑦) = 1 ∧ 𝑧 = ((𝑥↑2) + (𝑦↑2)))}
16	1, 15	2sqlem11 27380	. 2 ⊢ ((𝑃 ∈ ℙ ∧ (𝑃 mod 4) = 1) → 𝑃 ∈ ran (𝑤 ∈ ℤ[i] ↦ ((abs‘𝑤)↑2)))
17	1	2sqlem2 27369	. 2 ⊢ (𝑃 ∈ ran (𝑤 ∈ ℤ[i] ↦ ((abs‘𝑤)↑2)) ↔ ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ 𝑃 = ((𝑥↑2) + (𝑦↑2)))
18	16, 17	sylib 217	1 ⊢ ((𝑃 ∈ ℙ ∧ (𝑃 mod 4) = 1) → ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ 𝑃 = ((𝑥↑2) + (𝑦↑2)))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ∧ wa 394 = wceq 1533 ∈ wcel 2098 {cab 2702 ∃wrex 3060 ↦ cmpt 5226 ran crn 5673 ‘cfv 6543 (class class class)co 7416 1c1 11139 + caddc 11141 2c2 12297 4c4 12299 ℤcz 12588 mod cmo 13866 ↑cexp 14058 abscabs 15213 gcd cgcd 16468 ℙcprime 16641 ℤ[i]cgz 16897

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-11 2146 ax-12 2166 ax-ext 2696 ax-rep 5280 ax-sep 5294 ax-nul 5301 ax-pow 5359 ax-pr 5423 ax-un 7738 ax-cnex 11194 ax-resscn 11195 ax-1cn 11196 ax-icn 11197 ax-addcl 11198 ax-addrcl 11199 ax-mulcl 11200 ax-mulrcl 11201 ax-mulcom 11202 ax-addass 11203 ax-mulass 11204 ax-distr 11205 ax-i2m1 11206 ax-1ne0 11207 ax-1rid 11208 ax-rnegex 11209 ax-rrecex 11210 ax-cnre 11211 ax-pre-lttri 11212 ax-pre-lttrn 11213 ax-pre-ltadd 11214 ax-pre-mulgt0 11215 ax-pre-sup 11216 ax-addf 11217 ax-mulf 11218

This theorem depends on definitions: df-bi 206 df-an 395 df-or 846 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2528 df-eu 2557 df-clab 2703 df-cleq 2717 df-clel 2802 df-nfc 2877 df-ne 2931 df-nel 3037 df-ral 3052 df-rex 3061 df-rmo 3364 df-reu 3365 df-rab 3420 df-v 3465 df-sbc 3769 df-csb 3885 df-dif 3942 df-un 3944 df-in 3946 df-ss 3956 df-pss 3959 df-nul 4319 df-if 4525 df-pw 4600 df-sn 4625 df-pr 4627 df-tp 4629 df-op 4631 df-uni 4904 df-int 4945 df-iun 4993 df-iin 4994 df-br 5144 df-opab 5206 df-mpt 5227 df-tr 5261 df-id 5570 df-eprel 5576 df-po 5584 df-so 5585 df-fr 5627 df-se 5628 df-we 5629 df-xp 5678 df-rel 5679 df-cnv 5680 df-co 5681 df-dm 5682 df-rn 5683 df-res 5684 df-ima 5685 df-pred 6300 df-ord 6367 df-on 6368 df-lim 6369 df-suc 6370 df-iota 6495 df-fun 6545 df-fn 6546 df-f 6547 df-f1 6548 df-fo 6549 df-f1o 6550 df-fv 6551 df-isom 6552 df-riota 7372 df-ov 7419 df-oprab 7420 df-mpo 7421 df-of 7682 df-ofr 7683 df-om 7869 df-1st 7991 df-2nd 7992 df-supp 8164 df-tpos 8230 df-frecs 8285 df-wrecs 8316 df-recs 8390 df-rdg 8429 df-1o 8485 df-2o 8486 df-oadd 8489 df-er 8723 df-ec 8725 df-qs 8729 df-map 8845 df-pm 8846 df-ixp 8915 df-en 8963 df-dom 8964 df-sdom 8965 df-fin 8966 df-fsupp 9386 df-sup 9465 df-inf 9466 df-oi 9533 df-dju 9924 df-card 9962 df-pnf 11280 df-mnf 11281 df-xr 11282 df-ltxr 11283 df-le 11284 df-sub 11476 df-neg 11477 df-div 11902 df-nn 12243 df-2 12305 df-3 12306 df-4 12307 df-5 12308 df-6 12309 df-7 12310 df-8 12311 df-9 12312 df-n0 12503 df-xnn0 12575 df-z 12589 df-dec 12708 df-uz 12853 df-q 12963 df-rp 13007 df-fz 13517 df-fzo 13660 df-fl 13789 df-mod 13867 df-seq 13999 df-exp 14059 df-hash 14322 df-cj 15078 df-re 15079 df-im 15080 df-sqrt 15214 df-abs 15215 df-dvds 16231 df-gcd 16469 df-prm 16642 df-phi 16734 df-pc 16805 df-gz 16898 df-struct 17115 df-sets 17132 df-slot 17150 df-ndx 17162 df-base 17180 df-ress 17209 df-plusg 17245 df-mulr 17246 df-starv 17247 df-sca 17248 df-vsca 17249 df-ip 17250 df-tset 17251 df-ple 17252 df-ds 17254 df-unif 17255 df-hom 17256 df-cco 17257 df-0g 17422 df-gsum 17423 df-prds 17428 df-pws 17430 df-imas 17489 df-qus 17490 df-mre 17565 df-mrc 17566 df-acs 17568 df-mgm 18599 df-sgrp 18678 df-mnd 18694 df-mhm 18739 df-submnd 18740 df-grp 18897 df-minusg 18898 df-sbg 18899 df-mulg 19028 df-subg 19082 df-nsg 19083 df-eqg 19084 df-ghm 19172 df-cntz 19272 df-cmn 19741 df-abl 19742 df-mgp 20079 df-rng 20097 df-ur 20126 df-srg 20131 df-ring 20179 df-cring 20180 df-oppr 20277 df-dvdsr 20300 df-unit 20301 df-invr 20331 df-dvr 20344 df-rhm 20415 df-nzr 20456 df-subrng 20487 df-subrg 20512 df-drng 20630 df-field 20631 df-lmod 20749 df-lss 20820 df-lsp 20860 df-sra 21062 df-rgmod 21063 df-lidl 21108 df-rsp 21109 df-2idl 21148 df-rlreg 21234 df-domn 21235 df-idom 21236 df-cnfld 21284 df-zring 21377 df-zrh 21433 df-zn 21436 df-assa 21791 df-asp 21792 df-ascl 21793 df-psr 21846 df-mvr 21847 df-mpl 21848 df-opsr 21850 df-evls 22025 df-evl 22026 df-psr1 22107 df-vr1 22108 df-ply1 22109 df-coe1 22110 df-evl1 22244 df-mdeg 26006 df-deg1 26007 df-mon1 26084 df-uc1p 26085 df-q1p 26086 df-r1p 26087 df-lgs 27246

This theorem is referenced by: 2sqb 27383 2sqnn0 27389

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