{"title":"ON THE NONBENDABILITY OF CLOSED SURFACES OF TRIGONOMETRIC TYPE","authors":"Yu. A. Aminov","doi":"10.1070/SM1992V071N02ABEH001408","DOIUrl":"https://doi.org/10.1070/SM1992V071N02ABEH001408","url":null,"abstract":"In connection with a well-known problem on the existence of closed bendable surfaces in E3 the author considers the class of surfaces for which each component of the radius vector is a trigonometric polynomial in two variables. Two theorems on the nonbendability of surfaces in this class are proved, and an expression for the volume of the domain bounded by such a surface is established. Theorem 1 (the main theorem) asserts the nonbendability of a surface under the condition that some Diophantine equation does not have negative solutions. In this case the coefficients of the second fundamental form can be expressed in a finite-valued way in terms of the coefficients of the first fundamental form as algebraic expressions.","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121693108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"SOME CLASSICAL PROBLEMS IN THE THEORY OF ANALYTIC FUNCTIONS IN DOMAINS OF PARREAU-WIDOM TYPE","authors":"M. Samokhin","doi":"10.1070/SM1992V073N01ABEH002545","DOIUrl":"https://doi.org/10.1070/SM1992V073N01ABEH002545","url":null,"abstract":"Domains and Riemann surfaces of Parreau-Widom type are considered, along with the extension to these domains of classical results on the Hardy spaces and on representing measures and orthogonal measures (the theorems of the Riesz brothers), and so on.","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132825524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"SOLVABILITY OF SOME ELLIPTIC PROBLEMS WITH CRITICAL EXPONENT OF NONLINEARITY","authors":"I. Kuzin","doi":"10.1070/SM1991V068N02ABEH002108","DOIUrl":"https://doi.org/10.1070/SM1991V068N02ABEH002108","url":null,"abstract":"The problem is investigated, where is an open domain in , , is the critical exponent, and has a growth exponent less than the critical one.Theorems on the existence of a nontrivial solution of this problem is the space and spaces of more regular functions are proved under appropriate assumptions.Bibliography: 17 titles.","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115726904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"AFFINE MODULAR LIE ALGEBRAS","authors":"Y. Billig","doi":"10.1070/SM1991V070N02ABEH001387","DOIUrl":"https://doi.org/10.1070/SM1991V070N02ABEH001387","url":null,"abstract":"The paper is devoted to the construction of affine Kac-Moody algebras via defining relations arising from an integral affine Cartan matrix, in the case where the ground field has positive characteristic p > 7. Explicit constructions are given for algebras obtained in this way; in distinction with the zero characteristic case they have infinite-dimensional center. A theorem on the universality of this central extension is proved, and a series of finite-dimensional factors of affine modular algebras over the ideals having trivial intersection with Cartan's subalgebra is constructed. Moreover, a construction for the PI-envelopes of affine Kac-Moody algebras is given.","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116919673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"RIESZ TRANSFORMS AND PARTIAL DERIVATIVES","authors":"V. Yudin","doi":"10.1070/SM1991V069N02ABEH002115","DOIUrl":"https://doi.org/10.1070/SM1991V069N02ABEH002115","url":null,"abstract":"New estimates are given in the two-dimensional case for special operators that are linear combinations of Riesz transforms. They are used to investigate the distances between partial derivatives , , on the class","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121281724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"THE PONTRYAGIN PERSISTENCE PHENOMENON AND STABLE DUCK CYCLES OF MULTIDIMENSIONAL RELAXATION SYSTEMS WITH ONE SLOW VARIABLE","authors":"A. Kolesov, E. Mishchenko","doi":"10.1070/SM1991V070N01ABEH002117","DOIUrl":"https://doi.org/10.1070/SM1991V070N01ABEH002117","url":null,"abstract":"It is assumed that the equilibrium state of the relaxation system where and , passes generically through a point of discontinuity as varies. Under this condition stable duck cycles and cycles arising in a neighborhood of the equilibrium state are constructed.","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124900377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"THE ONE-DIMENSIONAL INVERSE SCATTERING PROBLEM FOR THE WAVE EQUATION","authors":"N. Grinberg","doi":"10.1070/SM1991V070N02ABEH001386","DOIUrl":"https://doi.org/10.1070/SM1991V070N02ABEH001386","url":null,"abstract":"A constructive method is given for solving the inverse scattering problem for the wave equation on the line and half-line. The slowness function is assumed to have a derivative everywhere except at a finite number of points, and both it and its derivative are assumed to be functions of bounded variation. In addition, the slowness n(x) is required to tend to 1 sufficiently rapidly as x→∞. In this case the slowness function can be reconstructed from the reflection coefficient.","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"37 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126154807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"APPLICATION OF DIVISOR THEORY TO THE NUMERICAL INTEGRATION OF PERIODIC FUNCTIONS OF SEVERAL VARIABLES","authors":"N. Temirgaliev","doi":"10.1070/SM1991V069N02ABEH001250","DOIUrl":"https://doi.org/10.1070/SM1991V069N02ABEH001250","url":null,"abstract":"The author exhibits an application of ideal theory to the exact integration of trigonometric polynomials with arbitrarily prescribed coefficient spectrum and to the approximate integration of functions of certain multidimensional classes E, W, and H.","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125267809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PROFINITE GROUPS THAT ACT ON TREES AND DO NOT HAVE FREE NONABELIAN PRO-p-SUBGROUPS","authors":"P. Zalesskii","doi":"10.1070/SM1991V069N01ABEH001204","DOIUrl":"https://doi.org/10.1070/SM1991V069N01ABEH001204","url":null,"abstract":"","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"275 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114441036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"ORIENTABILITY OF BUNDLES: OBSTRUCTION THEORY AND APPLICATIONS TO K-THEORY","authors":"Yuli B. Rudyak","doi":"10.1070/SM1991V068N02ABEH001934","DOIUrl":"https://doi.org/10.1070/SM1991V068N02ABEH001934","url":null,"abstract":"An obstruction theory is constructed for orientability of vector, piecewise-linear, and topological Rn-bundles and homotopy sphere bundles (spherical fibrations) in generalized cohomology theories. The results are applied to study the orientability of bundles in complex K-theory. In particular, it turns out that the problem of K-orientability for each of the four classes of bundles mentioned above is to be solved differently. Bibliography: 20 titles.","PeriodicalId":208776,"journal":{"name":"Mathematics of The Ussr-sbornik","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129871328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}