{"title":"Chebyshev Subspaces of Dirichlet Series","authors":"","doi":"10.3103/s0027132223060037","DOIUrl":"https://doi.org/10.3103/s0027132223060037","url":null,"abstract":"<span> <h3>Abstract</h3> <p>Haar and Kolmogorov found the necessary and sufficient conditions under which finite-dimensional subspaces in the space of continuous functions on an arbitrary compact set are Chebyshev. In this paper, it is proved that subspaces of Dirichlet series form Chebyshev subspaces in the space of <span> <span>(mathbf{C}(0,infty])</span> </span> of continuous and bounded functions in the interval <span> <span>((0,infty))</span> </span> that have a limit at infinity.</p> </span>","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"183 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140300441","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":"Normalization of Terms in Sharp Models of Logic of Proofs LP","authors":"","doi":"10.3103/s0027132223060049","DOIUrl":"https://doi.org/10.3103/s0027132223060049","url":null,"abstract":"<span> <h3>Abstract</h3> <p>A basic justification model is sharp when the evidence term constructors <span> <span>(cdot,+,!)</span> </span> in it mean exactly the application of modus ponens rule, the union and the verification of evidences. We construct an example of a sharp model for the logic of proofs <span>LP</span> and establish that in any sharp model of <span>LP</span> every proof term is equivalent to some proof polynomial.</p> </span>","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"4 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140300145","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":"Existence of Infinite, Everywhere Discontinuous Spectra of Upper Exponents of Oscillation of Signs, Zeros, and Roots of Third-Order Differential Equations","authors":"","doi":"10.3103/s0027132223050054","DOIUrl":"https://doi.org/10.3103/s0027132223050054","url":null,"abstract":"<span> <h3>Abstract</h3> <p>Examples of two linear homogeneous differential equations of the third order are constructed, the spectra of the upper strong exponents of oscillation of signs, zeros, and roots of one of which coincide with the set of rational numbers of the segment <span> <span>([0,1])</span> </span> and those of the other equation coincide with the set of irrational numbers of the segment <span> <span>([0,1])</span> </span> augmented with the number zero.</p> </span>","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"27 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138742799","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":"Reconstruction of the Schrödinger Operator with a Singular Potential on Half-Line by Its Prescribed Essential Spectrum","authors":"G. A. Agafonkin","doi":"10.3103/s0027132223040022","DOIUrl":"https://doi.org/10.3103/s0027132223040022","url":null,"abstract":"","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135055568","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":"Orthorecursive Expansion with Respect to Modified Faber–Schauder System","authors":"P. S. Stepanyants, A. K. Paunov","doi":"10.3103/s0027132223040095","DOIUrl":"https://doi.org/10.3103/s0027132223040095","url":null,"abstract":"","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135055866","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":"Invariant Sums of Products of Differentials","authors":"F. M. Malyshev","doi":"10.3103/s002713222304006x","DOIUrl":"https://doi.org/10.3103/s002713222304006x","url":null,"abstract":"","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135055865","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":"On the Computation Complexity of the Systems of Finite Abelian Group Elements","authors":"V. V. Kochergin","doi":"10.3103/s0027132223040034","DOIUrl":"https://doi.org/10.3103/s0027132223040034","url":null,"abstract":"","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135055571","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":"Jordan–Kronecker Invariants of Singular Pencils for Six-Dimensional Real Nilpotent Lie Algebras","authors":"F. I. Lobzin","doi":"10.3103/s0027132223040058","DOIUrl":"https://doi.org/10.3103/s0027132223040058","url":null,"abstract":"","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135055569","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":"Boundedness of the Set of Solutions to a Linear Homogeneous System Uniform Along the Initial Segment","authors":"N. L. Margolina, K. E. Shiryaev","doi":"10.3103/s0027132223040071","DOIUrl":"https://doi.org/10.3103/s0027132223040071","url":null,"abstract":"","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135055567","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":"On the Moments of Branching Random Walk in a Random Medium with a Gumbelian Potential","authors":"V. A. Kutsenko","doi":"10.3103/s0027132223040046","DOIUrl":"https://doi.org/10.3103/s0027132223040046","url":null,"abstract":"","PeriodicalId":42963,"journal":{"name":"Moscow University Mathematics Bulletin","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135055570","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}