Results 61 to 70 of about 3,554 (232)
Transactions of the London Mathematical Society, Volume 12, Issue 1, December 2025.Abstract In subwavelength physics, a challenging problem is to characterise the spectral properties of finite systems of subwavelength resonators. In particular, it is important to identify localised modes as well as bandgaps and associated mobility edges.
Habib Ammari +2 more
wiley +1 more source
Composition operator induced by ?(z) = sz + t for which |s|?1, |t|<1 and |s|+|t|?1
مجلة بغداد للعلوم, 2010 We study in this paper the composition operator that is induced by ?(z) = sz + t. We give a characterization of the adjoint of composiotion operators generated by self-maps of the unit ball of form ?(z) = sz + t for which |s|?1, |t|
Baghdad Science Journal
doaj +1 more source
Partially Isometric Toeplitz Operators [PDF]
Proceedings of the American Mathematical Society, 1965 It has been observed that the only Toeplitz operators that are isometric are those of the form To where q is an inner function on the unit disc (see e.g., [1, Theorem 8, Corollary 3]; the notation and terminology introduced there will be adhered to throughout this note).
Brown, Arlen, Douglas, R. G.
openaire +2 more sources
Space‐Time Boundary Elements on Graded Meshes for 3D Elastodynamics
International Journal for Numerical Methods in Engineering, Volume 126, Issue 20, 30 October 2025.ABSTRACT The solution to the elastodynamic equations in the exterior of a polygonal or polyhedral domain or a screen exhibits singularities at corners and edges. This paper presents a space‐time boundary element method in 3D on algebraically graded meshes to resolve these singularities, based on recently obtained error estimates for the weakly singular
Alessandra Aimi +3 more
wiley +1 more source
Journal of Function Spaces, 2016 Let T1 be a generalized Calderón-Zygmund operator or ±I (the identity operator), let T2 and T4 be the linear operators, and let T3=±I. Denote the Toeplitz type operator by Tb=T1MbIαT2+T3IαMbT4, where Mbf=bf and Iα is the fractional integral operator.
Bijun Ren, Enbin Zhang
doaj +1 more source
Sensitivity of Perron and Fiedler Eigenpairs to Structural Perturbations of a Network
Numerical Linear Algebra with Applications, Volume 32, Issue 5, October 2025.ABSTRACT One can estimate the change of the Perron and Fiedler values for a connected network when the weight of an edge is perturbed by analyzing relevant entries of the Perron and Fiedler vectors. This is helpful for identifying edges whose weight perturbation causes the largest change in the Perron and Fiedler values.
Silvia Noschese, Lothar Reichel
wiley +1 more source
Toeplitz Operators on the Weighted Bergman Space over the Two-Dimensional Unit Ball
Journal of Function Spaces, 2015 We extend the known results on commutative Banach algebras generated by Toeplitz operators with radial quasi-homogeneous symbols on the two-dimensional unit ball.
Alma García, Nikolai Vasilevski
doaj +1 more source
Dirac–Schrödinger operators, index theory and spectral flow
Journal of the London Mathematical Society, Volume 112, Issue 4, October 2025.Abstract In this article, we study generalised Dirac–Schrödinger operators in arbitrary signatures (with or without gradings), providing a general KK$\textnormal {KK}$‐theoretic framework for the study of index pairings and spectral flow. We provide a general Callias Theorem, which shows that the index (or the spectral flow, or abstractly the K ...
Koen van den Dungen
wiley +1 more source
Normal Truncated Toeplitz Operators [PDF]
Complex Analysis and Operator Theory, 2017 The characterization of normal truncated Toepltiz operators is first given by Chalendar and Timotin. We give an elementary proof of their result without using the algebraic properties of truncated Toeplitz operators.
openaire +2 more sources
A note on Berezin-Toeplitz quantization of the Laplace operator
Complex Manifolds, 2015 Given a Hodge manifold, it is introduced a self-adjoint operator on the space of endomorphisms of the global holomorphic sections of the polarization line bundle.
Vedova Alberto Della
doaj +1 more source