{"title":"Generalized Poisson kernel and solution of the Dirichlet problem for the radial Schrödinger equation","authors":"Víctor A. Vicente-Benítez","doi":"10.1007/s13324-026-01228-0","DOIUrl":"10.1007/s13324-026-01228-0","url":null,"abstract":"<div><p>We present an explicit construction of the solution to the Dirichlet boundary value problem for the radial Schrödinger equation in the unit ball, with a complex-valued potential <i>V</i> satisfying the condition <span>(int _0^1r|V(r)|dr<infty )</span>. The solution is based on the construction of an explicit orthogonal set of solutions for the radial equation. In the case of a Dirichlet problem with boundary data in <span>(W^{frac{1}{2},2}(mathbb {S}^{d-1}))</span>, the solution is expressed as a series expansion in terms of the so-called formal spherical polynomials. We establish conditions for the solvability and uniqueness of the Dirichlet problem. Based on this series representation, we introduce the concept of generalized Poisson kernel, develop its main properties, and investigate the conditions under which the Dirichlet problem, with a boundary condition being a complex Radon measure on <span>(mathbb {S}^{d-1})</span>, admits a solution in the sense of a distributional boundary values.</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13324-026-01228-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148465497","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":"On the existence of Nehari ground states for the nonlinear Schrödinger equation on discrete graphs","authors":"Setenay Akduman, Matthias Hofmann, Sedef Karakiliç","doi":"10.1007/s13324-026-01237-z","DOIUrl":"10.1007/s13324-026-01237-z","url":null,"abstract":"<div><p>We study standing waves for the nonlinear Schrödinger equation on a discrete graph. We characterize for a self-adjoint realizations of Schrödinger operators conditions related with the geometry of the graph that guarantee discreteness of the spectrum and study ground states on the generalized Nehari manifold in order to prove the existence of standing wave solutions in the self-focusing and defocusing cases. In this context, we show properties of the solutions, such as integrability. Finally, we discuss decay properties of solutions and the bifurcation of solutions from the trivial solution.</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13324-026-01237-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380256","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":"Bessel fractional calculus operators: perspective via Gaussian hypergeometric function","authors":"Zhengzhi Lu","doi":"10.1007/s13324-026-01230-6","DOIUrl":"10.1007/s13324-026-01230-6","url":null,"abstract":"<div><p>This paper investigates the theoretical foundations of Bessel fractional calculus. Distinctions are established between Bessel fractional operators and their classical counterparts. Semigroup theory is developed for the Bessel fractional integral operator, showing that it generates a <span>(C_{0})</span>-semigroup under specific conditions. Fundamental connections between differential and integral operators are analyzed, with comparisons drawn to classical theory. Furthermore, the structure of the solution space for homogeneous fractional differential equations is characterized. The influence of operator parameters–specifically the order and Bessel index <span>(nu )</span> on the resulting integral/differential operations is examined.</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380445","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":"Multiphase quadrature domains (existence and uniqueness)","authors":"Pu-Zhao Kow, Henrik Shahgholian, Tomas Sjödin","doi":"10.1007/s13324-026-01232-4","DOIUrl":"10.1007/s13324-026-01232-4","url":null,"abstract":"<div><p>The primary goal of this paper is to give a precise definition and prove existence and uniqueness of multiphase quadrature domains for subharmonic functions, ensuring that the prescribed measures are supported in the <i>interior</i> of the resulting domains. The approach to proving existence is based on a variational framework, where we minimize an energy functional over so called segregated states. In this respect, we refine earlier results in this direction. However, we also show that this approach alone is not enough for two reasons. First it seems difficult to obtain existence results which ensure that the interior support condition is satisfied. And second it may happen, as we show by an example, that a multiphase quadrature domain exists but is not a minimizer of the energy functional. The main novelty of this work is the study of minimizers, when they exist, of the energy functional over a subset of the segregated states determined by a natural constraint associated with the prescribed measures. From this approach we are able to prove uniqueness, and also give sufficient conditions for existence. We also give an example showing that, unlike the energy minimization and partial balayage approaches which are equivalent in the one-phase case, this equivalence breaks down already in the two-phase setting.</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13324-026-01232-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380828","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":"Fekete-Szegö inequality, coefficient estimates and construction methods for elastically starlike mappings on the unit ball of complex Banach spaces","authors":"Mihai Aron","doi":"10.1007/s13324-026-01235-1","DOIUrl":"10.1007/s13324-026-01235-1","url":null,"abstract":"<div><p>This paper is devoted to the study of a particular type of starlike mappings, namely, elastically starlike mappings on the unit ball of complex Banach spaces. We first introduce the concept of elastically starlikeness on the unit ball <span>(mathbb {B})</span> of a complex Banach space <i>X</i>, starting from the notion of elastically starlikeness in one complex variable, recently introduced by Aron [6]. In this more general setting, we present methods for constructing such mappings, using results for the class <span>(mathcal {M}(mathbb {B}))</span> and for starlike mappings. Furthermore, we establish strict inclusions between the classes of <span>(alpha )</span>-elastically starlike mappings for different values of the real parameter <span>(alpha )</span>, and between these and some classical classes of biholomorphic mappings. A central part of the paper is devoted to obtaining sharp coefficient estimates and Fekete-Szegö type inequalities for the class of elastically starlike mappings. We first consider the case of one complex variable, followed by the general setting of complex Banach spaces. Moreover, using the results obtained in the general case, we derive estimates for particular elastically starlike mappings, and for elastically starlike mappings on the unit polydisc <span>(U^n)</span> in <span>(mathbb {C}^n)</span>.</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13324-026-01235-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380902","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":"Cyclic polynomials in Dirichlet-type spaces of the unit bidisk","authors":"Rajkamal Nailwal, Aljaž Zalar","doi":"10.1007/s13324-026-01233-3","DOIUrl":"10.1007/s13324-026-01233-3","url":null,"abstract":"<div><p>For <span>(alpha in mathbb {R},)</span> we consider the scale of function spaces, namely the Dirichlet-type space <span>(mathcal {D}_{alpha })</span> consisting of holomorphic functions on the unit bidisk <span>(mathbb {D}^2)</span>, <span>(f(z,w)=sum _{k,l=0}^{infty }a_{kl}z^kw^l)</span> such that </p><div><div><span>$$begin{aligned} sum _{k,l=0}^{infty }(k+l+1)^alpha |a_{kl}|^2 < infty . end{aligned}$$</span></div></div><p>In this paper, we solve an open problem posed by Torkinejad Ziarati concerning the cyclicity of the polynomial <span>(2-z_1-z_2)</span> in <span>(mathcal {D}_alpha )</span> for <span>( frac{3}{2} < alpha le 2)</span>. We provide an affirmative answer and, as a consequence, complete the characterization of cyclic polynomials in <span>(mathcal {D}_alpha )</span>.</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13324-026-01233-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380903","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":"A uniqueness theorem on the inverse problem for the discontinuous Dirac operator","authors":"Lu Zhou, Yongxia Guo, Guangsheng Wei","doi":"10.1007/s13324-026-01231-5","DOIUrl":"10.1007/s13324-026-01231-5","url":null,"abstract":"<div><p>In this work, we consider an inverse problem for the discontinuous Dirac operator. It is shown that the unknown potential functions can be uniquely determined by a particular set of eigenvalues for an infinite set of different boundary conditions.</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148381017","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":"On Well-posedness and stability for a Keller-Segel-Navier-Stokes system in Lorentz spaces over real hyperbolic spaces","authors":"Dam Thi Ngoc Van, Pham Truong Xuan","doi":"10.1007/s13324-026-01226-2","DOIUrl":"10.1007/s13324-026-01226-2","url":null,"abstract":"<div><p>We establish the well-posedness and exponential stability of mild solutions for the Patlak-Keller-Segel-Navier-Stokes system on the real hyperbolic space <span>(mathbb {H}^d(mathbb {R}), (dgeqslant 2))</span>. We consider the system obtained by coupling a parabolic-elliptic Keller–Segel-type model with a Navier–Stokes-type equation. First, We employ the <span>(L^p-L^q)</span> estimates for both scalar and vectorial heat semigroups to derive useful interpolation inequalities, including <span>(L^{p,r}-L^{q,r})</span> estimates and Yamazaki-type estimates on <span>(mathbb {H}^d(mathbb {R}))</span>. Using these interpolation estimates, we establish the global well-posedness of mild solutions for the corresponding linear systems in the framework of Lorentz space <span>(L^{p,r}(mathbb {H}^d))</span> for <span>(d<p<2d)</span> and <span>(1leqslant r leqslant infty )</span>. Then, we combine the existence results of linear systems with fixed-point arguments to obtain the well-posedness of mild solutions for the semilinear systems. In addition, we prove an exponential stability for mild solutions by using again the interpolation estimates and the Gronwall inequality. Finally, we also consider the well-posedness and stability for the systems in the weak-<span>(L^p)</span> spaces, i.e., <span>(L^{p,infty }(mathbb {H}^d(mathbb {R})))</span> for the case <span>(dgeqslant 3)</span>.</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380901","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":"Local Besov–Bourgain–Morrey Spaces: Nontriviality, Boundedness of Local Operators, Duality, and Interpolation","authors":"Hao Peng, Dachun Yang, Yirui Zhao","doi":"10.1007/s13324-026-01225-3","DOIUrl":"10.1007/s13324-026-01225-3","url":null,"abstract":"<div><p>Let <span>(0<qle ple rle infty )</span> and <span>(tau in (0,infty ])</span>. In this article, we introduce a local variant <span>(mathcal {M}B_{q,r}^{p,tau })</span> of Besov–Bourgain–Morrey spaces <span>(mathcal {M}dot{B}_{q,r}^{p,tau })</span>, whose special case <span>(tau =r)</span> was originally introduced by J. Bourgain and has proved to play an important role in the study related to the Strichartz estimate and some partial differential equations. These local spaces <span>(mathcal {M}B_{q,r}^{p,tau })</span> include Bourgain–Lebesgue, local Morrey, and amalgam spaces as special cases. We find the sufficient and necessary conditions, respectively, for their nontriviality, for <span>(mathcal {M}dot{B}_{q,r}^{p,tau })</span> to be properly contained in <span>(mathcal {M}B_{q,r}^{p,tau })</span>, and also for both the boundedness and the Fefferman–Stein vector-valued maximal inequality about the local Hardy–Littlewood maximal operator on <span>(mathcal {M}B_{q,r}^{p,tau })</span>. Moreover, on <span>(mathcal {M}B_{q,r}^{p,tau })</span> we study their diversity, their duality, and their interpolation in terms of Calderón products. Using the Calderón product and a new pointwise sparse domination, we obtain the boundedness of local fractional integrals from Calderón products to <span>(mathcal {M}B_{q,r}^{p,tau })</span>. Moreover, we also obtain the boundedness of local Calderón–Zygmund operators on <span>(mathcal {M}B_{q,r}^{p,tau })</span>.</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323680","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":"Pointwise rotation for homeomorphisms with integrable distortion and controlled compression","authors":"Lauri Hitruhin, Banhirup Sengupta","doi":"10.1007/s13324-026-01227-1","DOIUrl":"10.1007/s13324-026-01227-1","url":null,"abstract":"<div><p>We obtain sharp rotation bounds for homeomorphisms <span>(f:mathbb {C}rightarrow mathbb {C})</span> whose distortion is in <span>(L^p_{loc})</span>, <span>(pge 1)</span>, and whose inverse have controlled modulus of continuity. The motivation to study this class of maps comes from so-called Yudovich solutions to planar Euler equations. Furthermore, we present examples proving sharpness in a strong sense, thereby settling the borderline case <span>(p=1)</span> in [5, Theorem 3].</p></div>","PeriodicalId":48860,"journal":{"name":"Analysis and Mathematical Physics","volume":"16 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323717","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}