V. L. Chernyshev, T. W. Hilberdink, D. S. Minenkov, V. E. Nazaikinskii
{"title":"Restricted Partitions: The Polynomial Case","authors":"V. L. Chernyshev, T. W. Hilberdink, D. S. Minenkov, V. E. Nazaikinskii","doi":"10.1134/S0016266322040074","DOIUrl":"10.1134/S0016266322040074","url":null,"abstract":"<p> We prove a restricted inverse prime number theorem for an arithmetical semigroup with polynomial growth of the abstract prime counting function. The adjective “restricted” refers to the fact that we consider the counting function of abstract integers of degree <span>(le t)</span> whose prime factorization may only contain the first <span>(k)</span> abstract primes (arranged in nondescending order of their degree). The theorem provides the asymptotics of this counting function as <span>(t,ktoinfty)</span>. The study of the discussed asymptotics is motivated by two possible applications in mathematical physics: the calculation of the entropy of generalizations of the Bose gas and the study of the statistics of propagation of narrow wave packets on metric graphs. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4817408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On Maximal Extensions of Nilpotent Lie Algebras","authors":"V. V. Gorbatsevich","doi":"10.1134/S0016266322040037","DOIUrl":"10.1134/S0016266322040037","url":null,"abstract":"<p> Extensions of finite-dimensional nilpotent Lie algebras, in particular, solvable extensions, are considered. Some properties of maximal extensions are proved. A counterexample to L. Šnobl’s conjecture concerning the uniqueness of maximal solvable extensions is constructed. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4524534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Unitary Flows with Tensor Simple Spectrum","authors":"V. V. Ryzhikov","doi":"10.1134/S0016266322040116","DOIUrl":"10.1134/S0016266322040116","url":null,"abstract":"<p> Unitary flows <span>(T_t)</span> of dynamical origin such that, for any countable <span>(Qsubset (0,+infty))</span>, the spectrum of the tensor product <span>(bigotimes_{qin Q} T_q )</span> is simple are constructed. All typical flows preserving a sigma-finite measure have this property. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4521281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On an Elliptic Operator Degenerating on the Boundary","authors":"V. E. Nazaikinskii","doi":"10.1134/S0016266322040104","DOIUrl":"10.1134/S0016266322040104","url":null,"abstract":"<p> Let <span>(Omegasubsetmathbb{R}^n)</span> be a bounded domain with smooth boundary <span>(partialOmega)</span>, let <span>(D(x)in C^infty(overlineOmega))</span> be a defining function of the boundary, and let <span>(B(x)in C^infty(overlineOmega))</span> be an <span>(ntimes n)</span> matrix function with self-adjoint positive definite values <span>(B(x )=B^*(x)>0)</span> for all <span>(xinoverlineOmega)</span> The Friedrichs extension of the minimal operator given by the differential expression <span>(mathcal{A}_0=-langlenabla,D(x )B(x)nablarangle)</span> to <span>(C_0^infty(Omega))</span> is described. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4524194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Approximations of the Images and Integral Funnels of the (L_p) Balls under a Urysohn-Type Integral Operator","authors":"A. Huseyin, N. Huseyin, Kh. G. Guseinov","doi":"10.1134/S0016266322040050","DOIUrl":"10.1134/S0016266322040050","url":null,"abstract":"<p> Approximations of the image and integral funnel of a closed ball of the space <span>(L_p)</span>, <span>(p>1)</span>, under a Urysohn-type integral operator are considered. A closed ball of the space <span>(L_p)</span>, <span>(p>1)</span>, is replaced by a set consisting of a finite number of piecewise constant functions, and it is proved that, for appropriate discretization parameters, the images of these piecewise constant functions form an internal approximation of the image of the closed ball. This result is applied to approximate the integral funnel of a closed ball of the space <span>(L_p)</span>, <span>(p>1)</span>, under a Urysohn-type integral operator by a set consisting of a finite number of points. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4524185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Semifinite Harmonic Functions on the Zigzag Graph","authors":"N. A. Safonkin","doi":"10.1134/S0016266322030042","DOIUrl":"10.1134/S0016266322030042","url":null,"abstract":"<p> We study semifinite harmonic functions on the zigzag graph, which corresponds to the Pieri rule for the fundamental quasisymmetric functions <span>({F_{lambda}})</span>. The main problem, which we solve here, is to classify the indecomposable semifinite harmonic functions on this graph. We show that these functions are in a natural bijective correspondence with some combinatorial data, the so-called semifinite zigzag growth models. Furthermore, we describe an explicit construction that produces a semifinite indecomposable harmonic function from every semifinite zigzag growth model. We also establish a semifinite analogue of the Vershik–Kerov ring theorem. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5175321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Criteria for the Property (UWE) and the a-Weyl Theorem","authors":"Chenhui Sun, Xiaohong Cao","doi":"10.1134/S0016266322030054","DOIUrl":"10.1134/S0016266322030054","url":null,"abstract":"<p> In this paper, the property (UWE) and the a-Weyl theorem for bounded linear operators are studied in terms of the property of topological uniform descent. Sufficient and necessary conditions for a bounded linear operator defined on a Hilbert space to have the property (UWE) and satisfy the a-Weyl theorem are established. In addition, new criteria for the fulfillment of the property (UWE) and the a-Weyl theorem for an operator function are discussed. As a consequence of the main theorem, results on the stability of the property (UWE) and the a-Weyl theorem are obtained. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5172988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cyclic Vectors and Invariant Subspaces of the Backward Shift Operator in Schwartz Modules","authors":"O. A. Ivanova, S. N. Melikhov","doi":"10.1134/S0016266322030030","DOIUrl":"10.1134/S0016266322030030","url":null,"abstract":"<p> Cyclic vectors and proper closed invariant subspaces of the backward shift operator in the Schwartz modules of entire functions of exponential type are described. The results are applied to describe ideals of the algebra of infinitely differentiable functions on a closed or open interval containing <span>(0)</span> with Duhamel product as multiplication. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5175320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On Poisson Semigroup Hypercontractivity for Higher-Dimensional Spheres","authors":"Yi. C. Huang","doi":"10.1134/S001626632203008X","DOIUrl":"10.1134/S001626632203008X","url":null,"abstract":"<p> In this note we consider a variant of a question of Mueller and Weissler raised in 1982, thereby complementing a classical result of Beckner on Stein’s conjecture and a recent result of Frank and Ivanisvili. More precisely, we show that, for <span>(1<pleq q<infty)</span> and <span>(ngeq1)</span>, the Poisson semigroup <span>(e^{-tsqrt{-Delta-(n-1)mathbb{P}}})</span> on the <span>(n)</span>-sphere is hypercontractive from <span>(L^p)</span> to <span>(L^q)</span> if and only if <span>(e^{-t}leqsqrt{(p-1)/(q-1)})</span>; here <span>(Delta)</span> is the Laplace–Beltrami operator on the <span>(n)</span>-sphere and <span>(mathbb{P})</span> is the projection operator onto spherical harmonics of degree <span>(geq1)</span>. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5175322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Parametric Korteweg–de Vries Hierarchy and Hyperelliptic Sigma Functions","authors":"E. Yu. Bunkova, V. M. Bukhshtaber","doi":"10.1134/S0016266322030029","DOIUrl":"10.1134/S0016266322030029","url":null,"abstract":"<p> In this paper, a parametric Korteweg–de Vries hierarchy is defined that depends on an infinite set of graded parameters <span>(a = (a_4,a_6,dots))</span>. It is shown that, for any genus <span>(g)</span>, the Klein hyperelliptic function <span>(wp_{1,1}(t,lambda))</span> defined on the basis of the multidimensional sigma function <span>(sigma(t, lambda))</span>, where <span>(t = (t_1, t_3,dots, t_{2g-1}))</span> and <span>(lambda = (lambda_4, lambda_6,dots, lambda_{4 g + 2}))</span>, specifies a solution to this hierarchy in which the parameters <span>(a)</span> are given as polynomials in the parameters <span>(lambda)</span> of the sigma function. The proof uses results concerning the family of operators introduced by V. M. Buchstaber and S. Yu. Shorina. This family consists of <span>(g)</span> third-order differential operators in <span>(g)</span> variables. Such families are defined for all <span>(g geqslant 1)</span>, the operators in each of them pairwise commute with each other and also commute with the Schrödinger operator. In this paper a relationship between these families and the Korteweg–de Vries parametric hierarchy is described. A similar infinite family of third-order operators on an infinite set of variables is constructed. The results obtained are extended to the case of such a family. </p>","PeriodicalId":575,"journal":{"name":"Functional Analysis and Its Applications","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5175319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}