Atsushi Inoue, Sean Ku, Jun Masamune, Radosław K. Wojciechowski
{"title":"Essential Self-Adjointness of the Laplacian on Weighted Graphs: Harmonic Functions, Stability, Characterizations and Capacity","authors":"Atsushi Inoue, Sean Ku, Jun Masamune, Radosław K. Wojciechowski","doi":"10.1007/s11040-025-09498-z","DOIUrl":"10.1007/s11040-025-09498-z","url":null,"abstract":"<div><p>We give two characterizations for the essential self-adjointness of the weighted Laplacian on birth–death chains. The first involves the edge weights and vertex measure and is classically known; however, we give another proof using stability results, limit point-limit circle theory and the connection between essential self-adjointness and harmonic functions. The second characterization involves a new notion of capacity. Furthermore, we also analyze the essential self-adjointness of Schrödinger operators, use the characterizations for birth–death chains and stability results to characterize essential self-adjointness for star-like graphs, and give some connections to the <span>(ell ^2)</span>-Liouville property.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Ricci Curvature and the Normalized Ricci Flow on Generalized Wallach Spaces","authors":"Nurlan A. Abiev","doi":"10.1007/s11040-025-09509-z","DOIUrl":"10.1007/s11040-025-09509-z","url":null,"abstract":"<div><p>We proved that the normalized Ricci flow does not preserve the positivity of the Ricci curvature of invariant Riemannian metrics on every generalized Wallach space with <span>(a_1+a_2+a_3le 1/2)</span>, in particular, such a property takes place on the homogeneous spaces <span>(operatorname {SU}(k+l+m)/operatorname {S}(operatorname {U}(k)times operatorname {U}(l) times operatorname {U}(m)))</span> and <span>(operatorname {Sp}(k+l+m)/operatorname {Sp}(k)times operatorname {Sp}(l) times operatorname {Sp}(m))</span> independently on their parameters <i>k</i>, <i>l</i> and <i>m</i>. We proved that the positivity of the Ricci curvature is preserved under the normalized Ricci flow on generalized Wallach spaces with <span>(a_1+a_2+a_3> 1/2)</span> if the conditions <span>(4left( a_j+a_kright) ^2ge (1-2a_i)(1+2a_i)^{-1})</span> are satisfied for all <span>({i,j,k}={1,2,3})</span>. We also established that the homogeneous spaces <span>(operatorname {SO}(k+l+m)/operatorname {SO}(k)times operatorname {SO}(l)times operatorname {SO}(m))</span> satisfy the above conditions if <span>(max {k,l,m}le 11)</span>, moreover, additional conditions were found to keep <span>(operatorname {Ric}>0)</span> in cases when <span>(max {k,l,m}le 11)</span> is violated. Answers have also been found to similar questions about maintaining or non-maintaining the positivity of the Ricci curvature on all other generalized Wallach spaces given in the classification of Yu. G. Nikonorov.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144090984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analysis of Gibbs Measures and Stability of Dynamical System Linked to (1,1/2)-Mixed Ising Model on ((m,k))-Ary Trees","authors":"Aminah Qawasmeh, Farrukh Mukhamedov, Hasan Akın","doi":"10.1007/s11040-025-09504-4","DOIUrl":"10.1007/s11040-025-09504-4","url":null,"abstract":"<div><p>This paper introduces a new (1,1/2) mixed spin Ising model (shortly, (1,1/2)-MSIM) having <span>(J_1)</span> and <span>(J_2)</span> competing interactions on (<i>m</i>, <i>k</i>)-ary trees. By constructing splitting Gibbs measures, we establish the presence of multiple Gibbs measures, which implies the occurrence of the phase transition for the (1, 1/2)-MSIM on the (<i>m</i>, <i>k</i>)-ary trees. Furthermore, the extremality of the two translation-invariant Gibbs measures is demonstrated for (1, <i>k</i>)-ary trees. Moreover, the extremality condition for the disordered phases is found and its non-extremality regimes are examined as well. It is well known that, to investigate lattice models on tree-like structures, conducting a stability analysis of the dynamical systems that represent the model and examining the behavior of the fixed points of these dynamical systems can provide significant insights into the model. We conducted a stability analysis around fixed points to investigate the behavior of the MSIM on the (<i>m</i>, <i>k</i>)-ary trees, also referred to as <i>k</i>-ary trees.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Gauge Transformations and Long-Time Asymptotics for the New Coupled Integrable Dispersionless Equations","authors":"Xumeng Zhou, Xianguo Geng, Minxin Jia, Yunyun Zhai","doi":"10.1007/s11040-025-09507-1","DOIUrl":"10.1007/s11040-025-09507-1","url":null,"abstract":"<div><p>This work aims to investigate the asymptotic behavior analysis of solutions to the Cauchy problem of new coupled integrable dispersionless equations. Utilizing the gauge transformations, spectral analysis and inverse scattering method, we show that the solutions of new coupled integrable dispersionless equations can be expressed in terms of the solutions of two matrix Riemann–Hilbert problems formulated in the complex <span>(lambda )</span>-plane. Applying the nonlinear steepest descent method to the two associated matrix-valued Riemann–Hilbert problems, we obtain precise leading-order asymptotic formulas and uniform error estimates for the solutions of new coupled integrable dispersionless equations.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143900710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Classification of (1+0) Two-Dimensional Hamiltonian Operators","authors":"Alessandra Rizzo","doi":"10.1007/s11040-025-09506-2","DOIUrl":"10.1007/s11040-025-09506-2","url":null,"abstract":"<div><p>In this paper, we study Hamiltonian operators which are sum of a first order operator and of a Poisson tensor, in two spatial independent variables. In particular, a complete classification of these operators is presented in two and three components, analyzing both the cases of degenerate and non degenerate leading coefficients.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11040-025-09506-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143888547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Felix Finster, Robert H. Jonsson, Magdalena Lottner, Albert Much, Simone Murro
{"title":"Notions of Fermionic Entropies for Causal Fermion Systems","authors":"Felix Finster, Robert H. Jonsson, Magdalena Lottner, Albert Much, Simone Murro","doi":"10.1007/s11040-025-09505-3","DOIUrl":"10.1007/s11040-025-09505-3","url":null,"abstract":"<div><p>The fermionic von Neumann entropy, the fermionic entanglement entropy and the fermionic relative entropy are defined for causal fermion systems. Our definition makes use of entropy formulas for quasi-free fermionic states in terms of the reduced one-particle density operator. Our definitions are illustrated in various examples for Dirac spinors in two- and four-dimensional Minkowski space, in the Schwarzschild black hole geometry and for fermionic lattices. We review area laws for the two-dimensional diamond and a three-dimensional spatial region in Minkowski space. The connection is made to the computation of the relative entropy using modular theory.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11040-025-09505-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Propagation of Chaos and Residual Dependence in Gibbs Measures on Finite Sets","authors":"Jonas Jalowy, Zakhar Kabluchko, Matthias Löwe","doi":"10.1007/s11040-025-09503-5","DOIUrl":"10.1007/s11040-025-09503-5","url":null,"abstract":"<div><p>We compare a mean-field Gibbs distribution on a finite state space on <i>N</i> spins to that of an explicit simple mixture of product measures. This illustrates the situation beyond the so-called <i>increasing propagation of chaos</i> introduced by Ben Arous and Zeitouni [3], where marginal distributions of size <span>(k=o(N))</span> are compared to product measures.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11040-025-09503-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143629691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xing Li, Anton Dzhamay, Galina Filipuk, Da-jun Zhang
{"title":"Recurrence Relations for the Generalized Laguerre and Charlier Orthogonal Polynomials and Discrete Painlevé Equations on the (D_{6}^{(1)}) Sakai Surface","authors":"Xing Li, Anton Dzhamay, Galina Filipuk, Da-jun Zhang","doi":"10.1007/s11040-025-09502-6","DOIUrl":"10.1007/s11040-025-09502-6","url":null,"abstract":"<div><p>This paper concerns the discrete version of the <i>Painlevé identification problem</i>, i.e., how to recognize a certain recurrence relation as a discrete Painlevé equation. Often some clues can be seen from the setting of the problem, e.g., when the recurrence is connected with some differential Painlevé equation, or from the geometry of the configuration of indeterminate points of the equation. The main message of our paper is that, in fact, this only allows us to identify the <i>configuration space</i> of the dynamic system, but not the dynamics themselves. The <i>refined version</i> of the identification problem lies in determining, up to the conjugation, the translation direction of the dynamics, which in turn requires the full power of the geometric theory of Painlevé equations. To illustrate this point, in this paper we consider two examples of such recurrences that appear in the theory of orthogonal polynomials. We choose these examples because they get regularized on the same family of Sakai surfaces, but at the same time are not equivalent, since they result in non-equivalent translation directions. In addition, we show the effectiveness of a recently proposed identification procedure for discrete Painlevé equations using Sakai’s geometric approach for answering such questions. In particular, this approach requires no a priori knowledge of a possible type of the equation.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Matrix Solutions of the Cubic Szegő Equation on the Real Line","authors":"Ruoci Sun","doi":"10.1007/s11040-025-09500-8","DOIUrl":"10.1007/s11040-025-09500-8","url":null,"abstract":"<div><p>This paper is dedicated to studying matrix solutions of the cubic Szegő equation on the real line, which is introduced in Pocovnicu [Anal PDE 4(3):379–404, 2011; Dyn Syst A 31(3):607–649, 2011] and Gérard–Pushnitski (Commun Math Phys 405:167, 2024), leading to the following cubic matrix Szegő equation on <span>({mathbb {R}})</span>, </p><div><div><span>$$begin{aligned} i partial _t U = Pi _{ge 0} left( U U ^* U right) , quad widehat{left( Pi _{ge 0} Uright) }(xi )= {textbf{1}}_{xi ge 0}{hat{U}}(xi )in {mathbb {C}}^{M times N}. end{aligned}$$</span></div></div><p>Inspired by the space-periodic case in Sun (The matrix Szegő equation, arXiv:2309.12136), we establish its Lax pair structure via double Hankel operators and Toeplitz operators. Then the explicit formula in Gérard–Pushnitski (Commun Math Phys 405:167, 2024) can be extended to two equivalent formulas in the matrix equation case, which both express every solution explicitly in terms of its initial datum and the time variable.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Novel Discrete Integrable System Related to Hyper-Elliptic Curves of Genus Two","authors":"Jing-Rui Wu, Xing-Biao Hu","doi":"10.1007/s11040-025-09501-7","DOIUrl":"10.1007/s11040-025-09501-7","url":null,"abstract":"<div><p>Motivated by the discrete-time Toda (HADT) equation and quotient-quotient-difference (QQD) scheme together with their hungry forms (hHADT equation and hQQD scheme), we derive a new class of discrete integrable systems by considering the determinant structures of bivariate orthogonal polynomials associated with the genus-two hyper-elliptic curves. The corresponding Lax pairs are expressed through the recurrence relations of this class of bivariate orthogonal polynomials. Our study emphasizes the richer structures of genus-two hyper-elliptic curves, in contrast to the genus-one curve considered in the HADT and QQD cases, as well as in the hHADT and hQQD cases.</p></div>","PeriodicalId":694,"journal":{"name":"Mathematical Physics, Analysis and Geometry","volume":"28 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}