On Isometric Immersion of Three-Dimensional Geometries $SL_2$, $Nil$ and $Sol$ into a Four-Dimensional Space of Constant Curvature

We prove the nonexistence of isometric immersion of geometries $\text{Nil}^3$, $\widetilde{SL}_2$ into the four-dimensional space $M_c^4$ of the constant curvature $c$. We establish that the geometry $\text{Sol}^3$ cannot be immersed into $M_c^4$ if $c \neq -1$ and find the analytic immersion of thi...

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Дата:2005
Автори: Masal'tsev, L. A., Масальцев, Л. А.
Формат: Стаття
Мова:Російська
Англійська
Опубліковано: Institute of Mathematics, NAS of Ukraine 2005
Онлайн доступ:https://umj.imath.kiev.ua/index.php/umj/article/view/3609
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Назва журналу:Ukrains’kyi Matematychnyi Zhurnal
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Ukrains’kyi Matematychnyi Zhurnal
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author Masal'tsev, L. A.
Масальцев, Л. А.
Масальцев, Л. А.
author_facet Masal'tsev, L. A.
Масальцев, Л. А.
Масальцев, Л. А.
author_sort Masal'tsev, L. A.
baseUrl_str https://umj.imath.kiev.ua/index.php/umj/oai
collection OJS
datestamp_date 2020-03-18T19:59:42Z
description We prove the nonexistence of isometric immersion of geometries $\text{Nil}^3$, $\widetilde{SL}_2$ into the four-dimensional space $M_c^4$ of the constant curvature $c$. We establish that the geometry $\text{Sol}^3$ cannot be immersed into $M_c^4$ if $c \neq -1$ and find the analytic immersion of this geometry into the hyperbolic space $H^4(-1)$.
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fulltext K�O�R�O�T�K�I���P�O�V�I�D�O�M�L�E�N�N�Q UDK 514 L. A. Masal\cev (Xar\kov. nac. un-t) OB YZOMETRYÇESKOM POHRUÛENYY TREXMERNÁX HEOMETRYJ SL !! 2, Nil, Sol V ÇETÁREXMERNOE PROSTRANSTVO POSTOQNNOJ KRYVYZNÁ We prove the nonexistence of isometric immersion of geometries Nil 3 , SL ! 2 into the four-dimensional space Mc 4 of the constant curvature c. We establish that the geometry Sol 3 cannot be immersed into Mc 4 if c ≠ –1 and find the analytic immersion of this geometry into the hyperbolic space H 4 1( )− . Dovedeno neisnuvannq izometryçnoho zanurennq heometrij Nil 3 , SL ! 2 u çotyryvymirnyj pros- tir Mc 4 stalo] kryvyny c. Vstanovleno, wo heometriq Sol 3 ne moΩe buty zanurena u Mc 4 pry c ≠ –1, i znajdeno ]] analityçne zanurennq v hiperboliçnyj prostir H 4 1( )− . V nastoqwej stat\e yssleduetsq vopros ob yzometryçeskom pohruΩenyy trexmern¥x heometryj Terstona SL ! 2 , Nil, Sol ·1, s. 112‚ v çet¥rexmernoe prostranstvo Mc 4 postoqnnoj sekcyonnoj kryvyzn¥ c. Analytyçesky zadaça svodytsq k yssledovanyg razreßymosty system¥ uravnenyj Haussa y Kodaccy v kaΩdom yz trex sluçaev, hde metryçeskyj tenzor gij y tenzor Rymana qvlqgtsq yzvestn¥my velyçynamy, a ßest\ neyzvestn¥x komponent bij vtoroho funda- mental\noho tenzora dolΩn¥ udovletvorqt\ systeme yz ßesty uravnenyj Haussa y vos\my uravnenyj Kodaccy. Poskol\ku systema uravnenyj qvlqetsq pereopredelennoj, estestvenno oΩydat\ otrycatel\noho otveta na vopros o suwestvovanyy lokal\noho yzometryçeskoho pohruΩenyq yzuçaem¥x rymanov¥x mnohoobrazyj. Tak v dejstvytel\nosty y proysxodyt dlq SL ! 2 y Nil, no v slu- çae s Sol neoΩydanno okaz¥vaetsq, çto ymeetsq pohruΩenye πtoho prostranst- va v çet¥rexmernoe hyperbolyçeskoe prostranstvo H4 postoqnnoj otryca- tel\noj kryvyzn¥ –1. NepohruΩaemost\ Nil v çet¥rexmernoe evklydovo prostranstvo b¥la dokazana v ·2‚ druhym sposobom. Otmetym, çto pry v¥- çyslenyy komponent tenzora Rymana Rijkl y symvolov Krystoffelq Γjk i m¥ pol\zovalys\ systemoj Maple. 1. NepohruΩaemost\ Nil 3 v Mc 4 . Trexmernaq heometryq Nil 3 predstav- lqet soboj dejstvytel\nug hruppu Ly s zakonom umnoΩenyq ( , , )( , , )x y z x y z′ ′ ′ = = ( , , )x x y y z z xy+ ′ + ′ + ′ + ′ s levoynvaryantnoj rymanovoj metrykoj ds2 = = dx dy dz xdy2 2 2+ + −( ) ·1, s. 123‚. Teorema 1. Ne suwestvuet yzometryçeskoho klassa C3 pohruΩenyq proyz- vol\noj oblasty heometryy Nil v prostranstvo postoqnnoj kryvyzn¥ Mc 4 . Dokazatel\stvo. Systema uravnenyj Haussa pohruΩenyq Nil v Mc 4 ymeet vyd ·3, s. 182‚ R ijkl = b b b b c g g g gik jl il jk ik jl il jk− + −( ). (1) © L. A. MASAL|CEV, 2005 ISSN 0041-6053. Ukr. mat. Ωurn., 2005, t. 57, # 3 421 422 L. A. MASAL|CEV Podstavlqq v (1) konkretn¥e v¥raΩenyq komponent tenzora Rymana, v¥çyslen- n¥e v Maple, poluçaem sledugwye ßest\ uravnenyj: R1212 = x2 3 4 − = b b b c x11 22 12 2 21− + +( ), R1313 = 1 4 = b b b c11 33 13 2− + , R2323 = 1 4 = b b b c22 33 23 2− + , (2) R1213 = – x 4 = b b b b cx11 23 13 12− − , R1223 = 0 = b b b b12 23 13 22− , R1323 = 0 = b b b b12 33 13 23− . Esly umnoΩyt\ pqtoe uravnenye system¥ (2) na b33 , a ßestoe uravnenye na b23 y v¥çest\, to poluçym b b b b13 22 33 23 2−( ) = 0. Otsgda s uçetom tret\eho urav- nenyq, esly c ≠ 1 4 , ymeem b13 = 0. Analohyçno, umnoΩaq pqtoe uravnenye na b23 , a ßestoe uravnenye na b22 y v¥çytaq, poluçaem b12 = 0. Teper\ moΩno v¥razyt\ yz pervoho, vtoroho y çetvertoho uravnenyj b22 , b33 , b23 çerez b11 y podstavyt\ v tret\e uravnenye. V rezul\tate poluçym b11 2 = c c x c − − − 0 25 0 752 , , , b22 = ( , ) ,0 25 0 752 11 1− − −( ) −c x c b , b33 = ( , )0 25 11 1− −c b , b23 = − − −( , )0 25 11 1c xb . Dalee yspol\zuem uravnenye Kodaccy b12 3, = b13 2, , kotoroe, poskol\ku nenu- lev¥e symvol¥ Krystoffelq est\ Γ22 1 = –x, Γ23 1 = −Γ13 2 = 1 2 , Γ12 2 = −Γ13 3 = x 2 , Γ12 3 = x2 1 2 − , pryvodytsq k vydu b xb x b22 23 2 332 1+ + −( ) = 0. Posle podstanovky v poslednee uravnenye bik poluçaem absurdnoe toΩdestvo. Ostaetsq yssledovat\ otdel\no sluçaj c = 1 4 . Tohda systema (2) prynymaet vyd –1 = b b b11 22 12 2− , 0 = b b b11 33 13 2− , 0 = b b b22 33 23 2− , (3) 0 = b b b b11 23 13 12− , 0 = b b b b12 23 13 22− , 0 = b b b b12 33 13 23− . Esly umnoΩyt\ çetvertoe uravnenye system¥ (3) na b12 , a pqtoe uravnenye na b11 y v¥çest\, to poluçym b b b b13 12 2 11 22−( ) = 0, otkuda s uçetom pervoho uravnenyq naxodym b13 = 0. UmnoΩaq çetvertoe uravnenye na b22 , pqtoe uravnenye na b12 y v¥çytaq, poluçaem b23 = 0. Dalee lehko naxodym b33 = 0. Yspol\zuq uravnenye Kodaccy C1) b32 1, = b31 2, , ymeem b22 = − b11. Rassmotrym teper\ sledugwye uravnenyq Kodaccy: C2) b11 2, = b12 1, , yly ∂ ∂ b y 11 = ∂ ∂ +b x x b12 122 , C3) b22 1, = b21 2, , yly − ∂ ∂ b y 12 = ∂ ∂ +b x x b11 112 . ISSN 0041-6053. Ukr. mat. Ωurn., 2005, t. 57, # 3 OB YZOMETRYÇESKOM POHRUÛENYY TREXMERNÁX HEOMETRYJ … 423 Zapyßem yx v sledugwem vyde: C2) ∂ ∂ ( )y e bx2 4 11 / = ∂ ∂ ( )x e bx2 4 12 / , C3) ∂ ∂ ( )x e bx2 4 11 / = − ∂ ∂ ( )y e bx2 4 12 / . Sledovatel\no, funkcyy U = e bx2 4 12 / y V = e bx2 4 11 / qvlqgtsq dejstvy- tel\noj y mnymoj çastqmy nekotoroj analytyçeskoj funkcyy U + i V pere- mennoho x + i y. No tohda uravnenye Haussa 1 = b b11 2 12 2+ protyvoreçyt tomu, çto funkcyq ln U V2 2+( ) dolΩna b¥t\ harmonyçeskoj, çto y zaverßaet dokaza- tel\stvo. 2. NepohruΩaemost\ SL ! 2 v Mc 4 . Trexmernaq heometryq SL ! 2 predstav- lqet soboj unyversal\nug nakr¥vagwug hrupp¥ SL2 s levoynvaryantnoj metrykoj. V ·1, s. 114‚ ukazano, çto SL ! 2 moΩno predstavyt\ kak rassloenye edynyçn¥x vektorov UH 2 v kasatel\nom rassloenyy nad hyperbolyçeskoj ploskost\g H 2 . Pust\ H 2 : ( x, y), y > 0 s metrykoj ds H2 2 = dx dy y 2 2 2 + . Tohda UH 2 s koordynatamy x, y, t qvlqetsq podmnohoobrazyem v kasatel\nom rassloenyy nad H 2 s metrykoj ds UH2 2 = ds D D H H2 2 2 + v v, , hde v = = y t y tcos , sin( ) y D iv = = d dxi jk i j kv v+ Γ , i = 1, 2 (komponent¥ absolgtnoho dyfferencyala vektora v v metryke H 2 ). S uçetom toho, çto Γ12 1 = Γ22 2 = − 1 y , Γ11 2 = 1 y , poluçaem ds UH2 2 = dx dy dx ydt y 2 2 2 2 + + +( ) . (4) Teorema 2. Ne suwestvuet yzometryçeskoho klassa C 3 pohruΩenyq proyz- vol\noj oblasty heometryy SL ! 2 v prostranstvo postoqnnoj kryvyzn¥ Mc 4 . Dokazatel\stvo. Zapyßem systemu uravnenyj Haussa pohruΩenyq metryky (4) v Mc 4 : R1212 = − 3 2 4y = b b b c y 11 22 12 2 4 2− + , R1313 = 1 4 2y = b b b c y 11 33 13 2 2− + , R2323 = 1 4 2y = b b b c y 22 33 23 2 2− + , (5) R1223 = − 1 4 3y = b b b b c y 12 23 13 22 3− − , R1332 = 0 = b b b b13 32 12 33− , R2113 = 0 = b b b b21 13 23 11− . ISSN 0041-6053. Ukr. mat. Ωurn., 2005, t. 57, # 3 424 L. A. MASAL|CEV Rassmotrym snaçala sluçaj c ≠ 1 4 . Kak y v sluçae system¥ (2), poluçym b12 = = b32 = 0. Zatem moΩno najty ostal\n¥e neyzvestn¥e: b11 = − −1 5 2 4 22 , c y b , b33 = 0 25 2 22 , − c y b , b13 = 0 25 3 22 , − c y b , b22 = − −1 75 2 , c y . Teper\, yspol\zuq uravnenye Kodaccy b12 3, = b13 2, y uçyt¥vaq sledugwye znaçenyq symvolov Krystoffelq metryky (4): Γ12 1 = − 3 2y , Γ23 1 = – Γ13 2 = − 1 2 , Γ22 2 = – 1 y , Γ11 2 = 2 y , Γ12 3 = 1 2y , Γ23 3 = 1 2y , poluçaem absurdnoe toΩdestvo. Yssleduem sluçaj c = 1 4 . Systema uravnenyj Haussa (5) prynymaet vyd b b b11 22 12 2− = − 2 4y , b b b11 33 13 2− = 0, b b b22 33 23 2− = 0, b b b b12 23 13 22− = 0, b b b b13 32 12 33− = 0, b b b b21 13 23 11− = 0. UmnoΩaq çetvertoe uravnenye poslednej system¥ na b11, a ßestoe urav- nenye na b12 y sklad¥vaq, s uçetom pervoho uravnenyq poluçaem b13 = 0. Um- noΩaq çetvertoe uravnenye na b12 , ßestoe uravnenye na b22 y sklad¥vaq, ymeem b23 = 0. Zatem yz pervoho, vtoroho, tret\eho y pqtoho uravnenyj sleduet b33 = 0, y ostaetsq odno uravnenye Haussa b b b11 22 12 2− = − 2 4y y try neyzvestn¥e funkcyy b11, b12 , b22 peremenn¥x x, y, z , kotor¥e dolΩn¥ ewe udovletvo- rqt\ ßesty uravnenyqm Kodaccy sledugweho vyda: C1) b12 3, = b13 2, , yly ∂ ∂ −b z b12 22 1 2 = 0, C2) b21 3, = b23 1, , yly ∂ ∂ +b z b12 11 1 2 = 0, C3) b11 2, = b12 1, , yly ∂ ∂ +b y b y 11 113 2 = ∂ ∂ −b x b y 12 222 , C4) b11 3, = b13 1, , yly ∂ ∂ −b z b11 21 1 2 = 0, C5) b22 1, = b21 2, , yly ∂ ∂ +b x y b22 12 1 2 = ∂ ∂ b y 12 , C6) b22 3, = b23 2, , yly ∂ ∂ +b z b22 21 1 2 = 0. Uravnenyq C7) b33 1, = b13 3, y C 8) b33 2, = b32 3, udovletvoren¥ toΩdest- venno. Sravnyvaq uravnenyq C1) y C2), naxodym b22 = – b11, y tohda uravne- nyq C4) y C6) ravnosyl\n¥. Zatem uravnenyq C3) y C5) moΩno perepysat\ v sledugwem vyde: ISSN 0041-6053. Ukr. mat. Ωurn., 2005, t. 57, # 3 OB YZOMETRYÇESKOM POHRUÛENYY TREXMERNÁX HEOMETRYJ … 425 C3) ∂ ∂    y b y 11 = ∂ ∂    x b y 12 , C5) ∂ ∂    y b y 12 = − ∂ ∂    x b y 11 . Otsgda vydno, çto funkcyy U = b y 12 y V = b y 11 dolΩn¥ predstavlqt\ soboj dejstvytel\nug y mnymug çasty nekotoroj analytyçeskoj funkcyy peremen- noho x + i y, pryçem yz uravnenyq Haussa sleduet U V2 2+ = 2 5y . Odnako tohda funkcyq ln U V2 2+( ) ne budet harmonyçeskoj, çto y zaverßaet dokazatel\stvo teorem¥ 2. 3. Yzometryçeskoe pohruΩenye Sol3 v Mc 4 . Trexmernaq heometryq Sol predstavlqet soboj hruppu Ly s zakonom umnoΩenyq ( , , )( , , )x y z x y z′ ′ ′ = ( , , )x e x y e y z zz z+ ′ + ′ + ′− y s levoynvaryantnoj metrykoj ds2 = e dxz2 2 + e dyz−2 2 + dz2 ·1, s. 127‚. Teorema 3. 1. Ne suwestvuet yzometryçeskoho klassa C 3 pohruΩenyq proyzvol\noj oblasty heometryy Sol3 v prostranstvo postoqnnoj kryvyzn¥ Mc 4 pry c ≠ –1. 2. Suwestvuet yzometryçeskoe analytyçeskoe pohruΩenye heometryy Sol3 v hyperbolyçeskoe prostranstvo H4 1( )− , naprymer x z z x e x x e x x e y x e y z z z z z z z z 0 0 1 2 3 4 2 1 2 2 1 2 2 1 2 2 1 2 2 0 0 0 0 = + = = = =                               + + − − − − cosh( ) cos sin cos sin ( ) ( ) ( ) ( ) , (6) hde H4 1( )− = x x x x x x x x x x x0 1 2 3 4 0 2 1 2 2 2 3 2 4 2 01 0, , , , ,( ) − + + + + = − >( ) — verxnqq pola hyperboloyda v psevdoevklydovom prostranstve R4 1, s metry- koj ds2 = − + + + +dx dx dx dx dx0 2 1 2 2 2 3 2 4 2 , z0 ∈ R — proyzvol\naq postoqnnaq. Dokazatel\stvo. Systema uravnenyj Haussa pohruΩenyq Sol3 v Mc 4 yme- et vyd R1212 = 1 = b b b c11 22 12 2− + , R1313 = −e z2 = b b b ce z 11 33 13 2 2− + , R2323 = − −e z2 = b b b ce z 22 33 23 2 2− − − , (7) R1223 = 0 = b b b b12 23 13 22− , ISSN 0041-6053. Ukr. mat. Ωurn., 2005, t. 57, # 3 426 L. A. MASAL|CEV R1332 = 0 = b b b b13 32 12 33− , R2113 = 0 = b b b b21 13 23 11− . Tak Ωe, kak y pry reßenyy system¥ (2), lehko poluçyt\, çto pry c ≠ –1 b12 = b13 = b23 = 0. Zatem naxodym ostal\n¥e koπffycyent¥ vtoroj funda- mental\noj form¥: b11 = 1 2− c e z , b22 = 1 2− −c e z , b33 = 1 1 + − c c . S pomow\g uravnenyq Kodaccy b11 3, = b13 1, lehko pryjty k protyvoreçyg y, sledovatel\no, pry c ≠ –1 ne suwestvuet yzometryçeskoho pohruΩenyq Sol3 v Mc 4 . V sluçae, kohda c = –1, systema (7) prynymaet vyd b b b11 22 12 2− = 2, b b b11 33 13 2− = 0, b b b22 33 23 2− = 0, b b b b12 23 13 22− = 0, b b b b13 32 12 33− = 0, b b b b21 13 23 11− = 0. Yz çetvertoho y ßestoho uravnenyj poslednej system¥ s uçetom pervoho uravnenyq sleduet b13 = b23 = 0. Zatem yz pervoho, vtoroho, tret\eho y pqtoho uravnenyj naxodym b33 = 0. Rassmatryvaq systemu uravnenyj Kodaccy, ubeΩ- daemsq, çto b12 = 0, b11 = c ez 1 , b22 = 2 1c e z− (hde c1 — proyzvol\naq postoqn- naq) udovletvorqgt vsem ym. Tohda, sohlasno yzvestnoj teoreme Bonne, suwestvuet yzometryçeskoe pohruΩenye Sol3 v H4 1( )− . Posle πtoho netrudno najty yzometryçeskoe pohruΩenye (6), pryvedennoe v formulyrovke teorem¥. V zaklgçenye otmetym, çto v obzore A. A. Borysenko ·4‚ dostatoçno polno osvewen¥ vopros¥ yzometryçeskoho pohruΩenyq prostranstvenn¥x form v prostranstva postoqnnoj kryvyzn¥, no poka malo yssledovan¥ zadaçy pohruΩe- nyq trex- y çet¥rexmern¥x heometryçeskyx struktur v sm¥sle Terstona v prostranstva postoqnnoj kryvyzn¥. 1. Skott P. Heometryy na trexmern¥x mnohoobrazyqx. – M.: Myr, 1986. – 163 s. 2. Rivertz H. J. An obstruction to isometric immersion of the threedimensional Heisenberg group into R 4 // Prepr. Ser. Pure Math. – 1999. – # 22. 3. ∏jzenxart L. P. Rymanova heometryq. – M.: Yzd-vo ynostr. lyt., 1948. – 316 s. 4. Borysenko A. A. Yzometryçeskye pohruΩenyq prostranstvenn¥x form v rymanov¥ y psev- dorymanov¥ prostranstva postoqnnoj kryvyzn¥ // Uspexy mat. nauk. – 2001. – 56, v¥p. 3. – S.S3S–S78. Poluçeno 01.12. 2003 ISSN 0041-6053. Ukr. mat. Ωurn., 2005, t. 57, # 3
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spelling umjimathkievua-article-36092020-03-18T19:59:42Z On Isometric Immersion of Three-Dimensional Geometries $SL_2$, $Nil$ and $Sol$ into a Four-Dimensional Space of Constant Curvature Об изометрическом погружении трехмерных геометрий $SL_2$, $Nil$, $Sol$ в четырехмерное пространство постоянной кривизны Masal'tsev, L. A. Масальцев, Л. А. Масальцев, Л. А. We prove the nonexistence of isometric immersion of geometries $\text{Nil}^3$, $\widetilde{SL}_2$ into the four-dimensional space $M_c^4$ of the constant curvature $c$. We establish that the geometry $\text{Sol}^3$ cannot be immersed into $M_c^4$ if $c \neq -1$ and find the analytic immersion of this geometry into the hyperbolic space $H^4(-1)$. Доведено неіснування ізометричного занурення геометрій $\text{Nil}^3$, $\widetilde{SL}_2$ у чотиривимірний простір $M_c^4$ сталої кривини $c$. Встановлено, що геометрія $\text{Sol}^3$ не може бути занурена у $M_c^4$ при $c \neq -1$, і знайдено її аналітичне занурення в гіперболічний простір $H^4(-1)$. Institute of Mathematics, NAS of Ukraine 2005-03-25 Article Article application/pdf https://umj.imath.kiev.ua/index.php/umj/article/view/3609 Ukrains’kyi Matematychnyi Zhurnal; Vol. 57 No. 3 (2005); 421–426 Український математичний журнал; Том 57 № 3 (2005); 421–426 1027-3190 rus en https://umj.imath.kiev.ua/index.php/umj/article/view/3609/3949 https://umj.imath.kiev.ua/index.php/umj/article/view/3609/3950 Copyright (c) 2005 Masal'tsev L. A.
spellingShingle Masal'tsev, L. A.
Масальцев, Л. А.
Масальцев, Л. А.
On Isometric Immersion of Three-Dimensional Geometries $SL_2$, $Nil$ and $Sol$ into a Four-Dimensional Space of Constant Curvature
title On Isometric Immersion of Three-Dimensional Geometries $SL_2$, $Nil$ and $Sol$ into a Four-Dimensional Space of Constant Curvature
title_alt Об изометрическом погружении трехмерных геометрий $SL_2$, $Nil$, $Sol$ в четырехмерное пространство постоянной кривизны
title_full On Isometric Immersion of Three-Dimensional Geometries $SL_2$, $Nil$ and $Sol$ into a Four-Dimensional Space of Constant Curvature
title_fullStr On Isometric Immersion of Three-Dimensional Geometries $SL_2$, $Nil$ and $Sol$ into a Four-Dimensional Space of Constant Curvature
title_full_unstemmed On Isometric Immersion of Three-Dimensional Geometries $SL_2$, $Nil$ and $Sol$ into a Four-Dimensional Space of Constant Curvature
title_short On Isometric Immersion of Three-Dimensional Geometries $SL_2$, $Nil$ and $Sol$ into a Four-Dimensional Space of Constant Curvature
title_sort on isometric immersion of three-dimensional geometries $sl_2$, $nil$ and $sol$ into a four-dimensional space of constant curvature
url https://umj.imath.kiev.ua/index.php/umj/article/view/3609
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AT masal039tsevla obizometričeskompogruženiitrehmernyhgeometrijsl2nilsolvčetyrehmernoeprostranstvopostoânnojkrivizny
AT masalʹcevla obizometričeskompogruženiitrehmernyhgeometrijsl2nilsolvčetyrehmernoeprostranstvopostoânnojkrivizny
AT masalʹcevla obizometričeskompogruženiitrehmernyhgeometrijsl2nilsolvčetyrehmernoeprostranstvopostoânnojkrivizny