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An approach to the construction of index formulas for elliptic operators on singular manifolds is suggested on the basis of K-theory of algebras and cyclic cohomology. The equivalence of Toeplitz and pseudodifferential quantizations, well…

Analysis of PDEs · Mathematics 2011-11-08 V. Nazaikinskii , G. Rozenblum , A. Savin , B. Sternin

We study discrete spectrum of self-adjoint Weyl pseudodifferential operators with discontinuous symbols of the form $1_\Omega \phi$ where $1_\Omega$ is the indicator of a domain in $\Omega\subset\mathbb R^2$, and $\phi\in C^\infty_0(\mathbb…

Analysis of PDEs · Mathematics 2025-06-24 Alexey Derkach , Alexander V. Sobolev

The aim of this note is to generalize the notion of Fredholm operator to an arbitrary $C^*$-algebra. Namely, we define "finite type" elements in an axiomatic way, and also we define Fredholm type element $a$ as such element of a given…

Operator Algebras · Mathematics 2018-01-09 Dragoljub J. Kečkić , Zlatko Lazović

This work develops a functional-analytic framework based on the transfinite iteration of a self-adjoint operator. Beginning with a densely defined self-adjoint operator $A$ on a Hilbert space $H$, a spectral-transform functor $\Phi$ is…

Functional Analysis · Mathematics 2025-08-08 Faruk Alpay , Hamdi Alakkad , Taylan Alpay

For the defocusing Nonlinear Schr\"odinger equation on the circle, we construct a Birkhoff map $\Phi$ which is tame majorant analytic in a neighborhood of the origin. Roughly speaking, majorant analytic means that replacing the coefficients…

Analysis of PDEs · Mathematics 2018-05-02 Alberto Maspero

Given any separable complex Hilbert space, any trace-class operator $B$ which does not have purely imaginary trace, and any generator $L$ of a norm-continuous one-parameter semigroup of completely positive maps we prove that there exists a…

Functional Analysis · Mathematics 2024-09-04 Frederik vom Ende

The port-Hamiltonian formulation is a powerful method for modeling and interconnecting systems of different natures. In this paper, the port-Hamiltonian formulation in tensorial form of a thick plate described by the Mindlin-Reissner model…

Analysis of PDEs · Mathematics 2020-10-07 Andrea Brugnoli , Daniel Alazard , Valérie Pommier-Budinger , Denis Matignon

In this paper we study the operator inequality \phi(X)\leq X and the operator equation \phi(X)= X, where \phi is a w^*-continuous positive (resp. completely positive) linear map on B(H). We show that their solutions are in one-to-one…

Operator Algebras · Mathematics 2007-05-23 Gelu Popescu

Let $k$ be a field of characteristic zero. Let $F = X + H$ be a polynomial mapping from $k^n \to k^n$, where $X$ is the identity mapping and $H$ has only degree two terms and higher. We say that the Jacobian matrix $JH$ of $H$ is strongly…

Algebraic Geometry · Mathematics 2022-05-25 Samuel G. G. Johnston

Let $(X,\gamma)$ be a compact, irreducible Hermitian complex space of complex dimension $m$ and with $\mathrm{dim}(\mathrm{sing}(X))=0$. Let $(F,\tau)\rightarrow X$ be a Hermitian holomorphic vector bundle over $X$ and let us denote with…

Differential Geometry · Mathematics 2024-06-18 Francesco Bei

We study the existence of hypercyclic algebras for convolution operators $\Phi(D)$ on the space of entire functions whose symbol $\Phi$ has unimodular constant term. In particular, we provide new eigenvalue criteria for the existence of…

Functional Analysis · Mathematics 2019-05-09 J. Bes , R. Ernst , A. Prieto

We prove a formula expressing a general n by n Toeplitz determinant as a Fredholm determinant of an operator 1-K acting on l_2({n,n+1,...}), where the kernel K admits an integral representation in terms of the symbol of the original…

Classical Analysis and ODEs · Mathematics 2007-05-23 Alexei Borodin , Andrei Okounkov

In this paper we show that quasisimilar $n$-tuples of tensor products of $m$-isometric operators have the same spectra, essential spectra and indices. The properties of single Fredholm operators possess \cite{4} is related to an important…

Functional Analysis · Mathematics 2025-10-13 Salah Mecheri

This article is concerned with the semi-classical limits of matrix elements $<F \phi_j, \phi_j>$ of eigenfunctions of the Laplacian $\Delta_g$ of a compact Riemannian manifold $(M, g)$ with respect to a Fourier integral operator $F$ on…

Spectral Theory · Mathematics 2014-06-03 Steve Zelditch

In this note, we consider a Fourier integral operator defined by \begin{align*} T_{\phi,a}f(x) = \int_{\mathbb{R}^{n}}e^{i\phi(x,\xi)}a(x,\xi)\widehat{f} \xi)d\xi, \end{align*}here $a$ is the amplitude, and $\phi$ is the phase. Let…

Differential Geometry · Mathematics 2024-08-29 Xiaofeng Ye , Chunjie Zhang , Xiangrong Zhu

We consider elliptic operators associated with discrete groups of quantized canonical transformations. In order to be able to apply results from algebraic index theory, we define the localized algebraic index of the complete symbol of an…

Operator Algebras · Mathematics 2020-08-04 Anton Savin , Elmar Schrohe

We consider discretizations of the hyper-singular integral operator on closed surfaces and show that the inverses of the corresponding system matrices can be approximated by blockwise low-rank matrices at an exponential rate in the block…

Numerical Analysis · Mathematics 2017-12-04 Markus Faustmann , Jens Markus Melenk , Dirk Praetorius

The global qualitative behaviour of fields of principal directions for the graph of a real valued polynomial function $f$ on the plane are studied. We provide a Poincar\'e-Hopf type formula where the sum over all indices of the principal…

Differential Geometry · Mathematics 2021-06-24 Brendan Guilfoyle , Adriana Ortiz-Rodríguez

Wiener-Hopf plus Hankel operators acting between Lebesgue spaces on the real line are studied in view of their invertibility, one sided-invertibility, Fredholm, and semi-Fredholm properties. This is done in two different cases: (i) when the…

Functional Analysis · Mathematics 2007-05-23 G. Bogveradze , L. P. Castro

In [10], Halmos proved an interesting result that the set of irreducible operators is dense in $\mathcal B(\mathcal H)$ in the sense of Hilbert-Schmidt approximation. In a von Neumann algebra $\mathcal M$ with separable predual, an operator…

Operator Algebras · Mathematics 2020-06-23 Rui Shi
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