{"title":"On Kernels of Invariant Schrödinger Operators with Point Interactions. Grinevich–Novikov Conjecture","authors":"M. M. Malamud, V. V. Marchenko","doi":"10.1134/S1064562424701904","DOIUrl":"10.1134/S1064562424701904","url":null,"abstract":"<p>According to Berezin and Faddeev, a Schrödinger operator with point interactions –Δ + <span>(sumlimits_{j = 1}^m {{alpha }_{j}}delta (x - {{x}_{j}}),X = { {{x}_{j}}} _{1}^{m} subset {{mathbb{R}}^{3}},{ {{alpha }_{j}}} _{1}^{m} subset mathbb{R},)</span> is any self-adjoint extension of the restriction <span>({{Delta }_{X}})</span> of the Laplace operator <span>( - Delta )</span> to the subset <span>({ f in {{H}^{2}}({{mathbb{R}}^{3}}):f({{x}_{j}}) = 0,;1 leqslant j leqslant m} )</span> of the Sobolev space <span>({{H}^{2}}({{mathbb{R}}^{3}}))</span>. The present paper studies the extensions (realizations) invariant under the symmetry group of the vertex set <span>(X = { {{x}_{j}}} _{1}^{m})</span> of a regular <i>m</i>-gon. Such realizations <b>H</b><sub><i>B</i></sub> are parametrized by special circulant matrices <span>(B in {{mathbb{C}}^{{m times m}}})</span>. We describe all such realizations with non-trivial kernels. А Grinevich–Novikov conjecture on simplicity of the zero eigenvalue of the realization <b>H</b><sub><i>B</i></sub> with a scalar matrix <span>(B = alpha I)</span> and an even <i>m</i> is proved. It is shown that for an odd <i>m</i> non-trivial kernels of all realizations <b>H</b><sub><i>B</i></sub> with scalar <span>(B = alpha I)</span> are two-dimensional. Besides, for arbitrary realizations <span>((B ne alpha I))</span> the estimate <span>(dim (ker {{{mathbf{H}}}_{B}}) leqslant m - 1)</span> is proved, and all invariant realizations of the maximal dimension <span>(dim (ker {{{mathbf{H}}}_{B}}) = m - 1)</span> are described. One of them is the Krein realization, which is the minimal positive extension of the operator <span>({{Delta }_{X}})</span>.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 2","pages":"125 - 129"},"PeriodicalIF":0.5,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140884546","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":"Induced Forests and Trees in Erdős–Rényi Random Graph","authors":"M. B. Akhmejanova, V. S. Kozhevnikov","doi":"10.1134/S1064562424701886","DOIUrl":"10.1134/S1064562424701886","url":null,"abstract":"<p>We prove that the size of the maximum induced forest (of bounded and unbounded degree) in the binomial random graph <span>(G(n,p))</span> for <span>({{C}_{varepsilon }}{text{/}}n < p < 1 - varepsilon )</span> with an arbitrary fixed <span>(varepsilon > 0)</span> is concentrated in an interval of size <span>(o(1{text{/}}p))</span>. We also show 2-point concentration for the size of the maximum induced forest (and tree) of bounded degree in <span>(G(n,p))</span> for <i>p</i> = const.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 2","pages":"117 - 120"},"PeriodicalIF":0.5,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140884741","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":"A Joint Logic of Problems and Propositions","authors":"S. A. Melikhov","doi":"10.1134/S1064562424701916","DOIUrl":"10.1134/S1064562424701916","url":null,"abstract":"<p>In a 1985 commentary to his collected works, Kolmogorov informed the reader that his 1932 paper <i>On the interpretation of intuitionistic logic</i> “was written in hope that with time, the logic of solution of problems [i.e., intuitionistic logic] will become a permanent part of a [standard] course of logic. A unified logical apparatus was intended to be created, which would deal with objects of two types—propositions and problems.” We construct such a formal system as well as its predicate version, QHC, which is a conservative extension of both the intuitionistic predicate calculus QH and the classical predicate calculus QC. The axioms of QHC are obtained as a result of a simultaneous formalization of two well-known alternative explanations of intiuitionistic logic: (1) Kolmogorov’s problem interpretation (with familiar refinements by Heyting and Kreisel) and (2) the proof interpretation by Orlov and Heyting, as clarified and extended by Gödel.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 2","pages":"130 - 139"},"PeriodicalIF":0.5,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140884550","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":"Exact Estimates of Functions in Sobolev Spaces with Uniform Norm","authors":"D. D. Kazimirov, I. A. Sheipak","doi":"10.1134/S1064562424701862","DOIUrl":"10.1134/S1064562424701862","url":null,"abstract":"<p>For functions from the Sobolev space <span>(overset{circ}{W}{} _{infty }^{n}[0;1])</span> and an arbitrary point <span>(a in (0;1))</span>, the best estimates are obtained in the inequality <span>({text{|}}f(a){text{|}} leqslant {{A}_{{n,0,infty }}}(a), cdot ,{text{||}}{{f}^{{(n)}}}{text{|}}{{{text{|}}}_{{{{L}_{infty }}[0;1]}}})</span>. The connection of these estimates with the best approximations of splines of a special type by polynomials in <span>({{L}_{1}}[0;1])</span> and with the Peano kernel is established. Exact constants of the embedding of the space <span>(overset{circ}{W}{}_{infty }^{n}[0;1])</span> in <span>({{L}_{infty }}[0;1])</span> are found.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 2","pages":"107 - 111"},"PeriodicalIF":0.5,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140625571","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":"TOMMANO—Virtualised Network Functions Management in Cloud Environment based on the TOSCA Standard","authors":"R. K. Stolyarov, V. V. Shvetcova, O. D. Borisenko","doi":"10.1134/S1064562424701850","DOIUrl":"10.1134/S1064562424701850","url":null,"abstract":"<p>Since 2012 NFV (Network Functions Virtualisation) technology has evolved significantly and became widespread. Before the advent of this technology, proprietary network devices had to be used to process traffic. NFV technology allows you to simplify the configuration of network functions and reduce the cost of traffic processing by using software modules running on completely standard datacenter servers (in virtual machines). However, deploying and maintaining virtualised network functions (such as firewall, NAT, spam filter, access speed restriction) in the form of software components, changing the configurations of these components, and manually configuring traffic routing are still complicated operations. The problems described exist due to the huge number of network infrastructure components and differences in the functionality of chosen software, network operating systems and cloud platforms. In particular, the problem is relevant for the biomedical data analysis platform of the world-class Scientific Center of Sechenov University. In this article, we propose a solution to this problem by creating a framework TOMMANO that allows you to automate the deployment of virtualised network functions on virtual machines in cloud environments. It converts OASIS TOSCA [5, 6] declarative templates in notation corresponding to the ETSI MANO [2] for NFV standard into normative TOSCA templates and sets of Ansible scripts. Using these outputs an application containing virtualised network functions can be deployed by the TOSCA orchestrator in any cloud environment it supports. The developed TOMMANO framework received a certificate of state registration of the computer program no. 2023682112 dated October 23, 2023. In addition, this article provides an example of using this framework for the automatic deployment of network functions. In this solution Cumulus VX is used as the provider operating system of network functions. Clouni is used as an orchestrator. Openstack is used as a cloud provider.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 1","pages":"84 - 92"},"PeriodicalIF":0.5,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140625746","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":"Topological Product of Modal Logics with the McKinsey Axiom","authors":"A. V. Kudinov","doi":"10.1134/S1064562424701825","DOIUrl":"10.1134/S1064562424701825","url":null,"abstract":"<p>We consider products of modal logics in topological semantics and prove that the topological product of S4.1 and S4 is the fusion of logics S4.1 and S4 plus one extra asiom. This is an example of a topological product of logics that is greater than the fusion but less than the semiproduct of the corresponding logics. We also show that this product is decidable.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 1","pages":"66 - 72"},"PeriodicalIF":0.5,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140625567","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}
V. O. Manturov, A. Ya. Kanel-Belov, S. Kim, F. K. Nilov
{"title":"Two-Dimensional Self-Trapping Structures in Three-Dimensional Space","authors":"V. O. Manturov, A. Ya. Kanel-Belov, S. Kim, F. K. Nilov","doi":"10.1134/S1064562424701837","DOIUrl":"10.1134/S1064562424701837","url":null,"abstract":"<p>It is known that a finite set of convex figures on the plane with disjoint interiors has at least one outermost figure, i.e., one that can be continuously moved “to infinity” (outside a large circle containing the other figures), while the other figures are left stationary and their interiors are not crossed during the movement. It has been discovered that, in three-dimensional space, there exists a phenomenon of self-trapping structures. A self-trapping structure is a finite (or infinite) set of convex bodies with non-intersecting interiors, such that if all but one body are fixed, that body cannot be “carried to infinity.” Since ancient times, existing structures have been based on the consideration of layers made of cubes, tetrahedra, and octahedra, as well as their variations. In this work, we consider a fundamentally new phenomenon of two-dimensional self-trapping structures: a set of two-dimensional polygons in three-dimensional space, where each polygonal tile cannot be carried to infinity. Thin tiles are used to assemble self-trapping decahedra, from which second-order structures are then formed. In particular, a construction of a column composed of decahedra is presented, which is stable when we fix two outermost decahedra, rather than the entire boundary of the layer, as in previously investigated structures.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 1","pages":"73 - 79"},"PeriodicalIF":0.5,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140625748","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}
A. Ya. Kanel-Belov, M. Golafshan, S. G. Malev, R. P. Yavich
{"title":"Finding the Area and Perimeter Distributions for Flat Poisson Processes of a Straight Line and Voronoi Diagrams","authors":"A. Ya. Kanel-Belov, M. Golafshan, S. G. Malev, R. P. Yavich","doi":"10.1134/S1064562424701801","DOIUrl":"10.1134/S1064562424701801","url":null,"abstract":"<p>The study of distribution functions (with respect to areas, perimeters) for partitioning a plane (space) by a random field of straight lines (hyperplanes) and for obtaining Voronoi diagrams is a classical problem in statistical geometry. Moments for such distributions have been investigated since 1972 [1]. We give a complete solution of these problems for the plane, as well as for Voronoi diagrams. The following problems are solved: 1. A random set of straight lines is given on the plane, all shifts are equiprobable, and the distribution law has the form <span>(F(varphi ).)</span> What is the area (perimeter) distribution of the parts of the partition? 2. A random set of points is marked on the plane. Each point <i>A</i> is associated with a “region of attraction,” which is a set of points on the plane to which <i>A</i> is the closest of the marked set. The idea is to interpret a random polygon as the evolution of a segment on a moving one and construct kinetic equations. It is sufficient to take into account a limited number of parameters: the covered area (perimeter), the length of the segment, and the angles at its ends. We show how to reduce these equations to the Riccati equation using the Laplace transform.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 1","pages":"56 - 61"},"PeriodicalIF":0.5,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140625626","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 the Orbital Stability of Pendulum Motions of a Rigid Body in the Hess Case","authors":"B. S. Bardin, A. A. Savin","doi":"10.1134/S1064562424701795","DOIUrl":"10.1134/S1064562424701795","url":null,"abstract":"<p>Given a heavy rigid body with one fixed point, we investigate the problem of orbital stability of its periodic motions. Based on the analysis of the linearized system of equations of perturbed motion, the orbital instability of the pendulum rotations is proved. In the case of pendulum oscillations, a transcendental situation occurs, when the question of stability cannot be solved using terms of an arbitrarily high order in the expansion of the Hamiltonian of the equations of perturbed motion. It is proved that the pendulum oscillations are orbitally unstable for most values of the parameters.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 1","pages":"52 - 55"},"PeriodicalIF":0.5,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140625749","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 Reconstruction of Kolmogorov Operators with Discontinuous Coefficients","authors":"V. I. Bogachev, S. V. Shaposhnikov","doi":"10.1134/S1064562424600052","DOIUrl":"10.1134/S1064562424600052","url":null,"abstract":"<p>We obtain broad sufficient conditions for reconstructing the coefficients of a Kolmogorov operator by means of a solution to the Cauchy problem for the corresponding Fokker–Planck–Kolmogorov equation.</p>","PeriodicalId":531,"journal":{"name":"Doklady Mathematics","volume":"109 2","pages":"103 - 106"},"PeriodicalIF":0.5,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140629523","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}