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In this paper, we introduce the notion of Shilov boundary ideal for a local operator system and investigate some of its properties.

Operator Algebras · Mathematics 2024-10-31 Maria Joiţa

We prove an implicit function theorem and an inverse function theorem for free noncommutative functions over operator spaces and on the set of nilpotent matrices. We apply these results to study dependence of the solution of the initial…

Operator Algebras · Mathematics 2015-06-30 Gulnara Abduvalieva , Dmitry S. Kaliuzhnyi-Verbovetskyi

We investigate the traceability of positive integral operators on $L^2(X,\mu)$ when $X$ is a Hausdorff locally compact second countable space and $\mu$ is a non-degenerate, $\sigma$-finite and locally finite Borel measure. This setting…

Functional Analysis · Mathematics 2018-09-25 Mario H. Castro , Valdir A. Menegatto , Ana P. Peron

We study a positivity preservation property for Schr\"odinger operators with singular potential on geodesically complete Riemannian manifolds with non-negative Ricci curvature. We apply this property to the question of self-adjointness of…

Analysis of PDEs · Mathematics 2014-12-24 Ognjen Milatovic

This paper explores idempotent and nilpotent operators in bicomplex spaces, focusing on their properties and behavior. We define idempotent and nilpotent matrices in this framework and derive related results. Several theorems are presented…

Representation Theory · Mathematics 2025-09-03 Anjali Anjali , Akhil Prakash , Amita Amita , Neeraj Kumar Tomar

Let G be a finite group scheme over an algebraically closed field of positive characteristic. Assume further that the connected component of G is unipotent. It is shown that the projectivity of a rational G-module can be detected on a…

Representation Theory · Mathematics 2019-09-25 Christopher P. Bendel

The Euclidean operator radius of two bounded linear operators in the Hilbert $C^*$-module over $\A$ is given some precise bounds. Their relationship to recent findings in the literature that offer precise upper and lower bounds on the…

Functional Analysis · Mathematics 2023-07-06 M. H. M. Rashid

We continue our study of the general theory of possibly nonselfadjoint algebras of operators on a Hilbert space, and modules over such algebras, developing a little more technology to connect `nonselfadjoint operator algebra' with the…

Operator Algebras · Mathematics 2007-05-23 David P. Blecher

This paper concerns positive domination property of compact operators on pre-Riesz spaces. The method is embedding the pre-Riesz space to the Riesz completion. It extends the order continuous norms in pre-Riesz spaces to Riesz completions.…

Functional Analysis · Mathematics 2018-09-18 Onno van Gaans , Feng Zhang

We give a direct proof for the positivity of Kirillov's character on the convolution algebra of smooth, compactly supported functions on a connected, simply connected nilpotent Lie group $G$. Then we use this positivity result to construct…

Representation Theory · Mathematics 2020-03-17 Ehssan Khanmohammadi

We develop a systematic study of the schur tensor product both in the category of operator spaces and in that of $C^*$-algebras.

Operator Algebras · Mathematics 2013-08-22 Vandana Rajpal , Ajay Kumar , Takashi Itoh

We study invertibility and compactness of positive Toeplitz operators associated to a continuous Parseval frame on a Hilbert space. As applications, we characterize compactness of affine and Weyl-Heisenberg localization operators as well as…

Functional Analysis · Mathematics 2021-11-22 A. Walton Green , Mishko Mitkovski

We write arbitrary separable nuclear C*-algebras as limits of inductive systems of finite-dimensional C*-algebras with completely positive connecting maps. The characteristic feature of such CPC*-systems is that the maps become more and…

Operator Algebras · Mathematics 2024-10-10 Kristin Courtney , Wilhelm Winter

Let $A$ be a (non-unital, in general) C*-algebra with center $Z(M(A))$ of its multiplier algebra, and let $\{ X, \langle .,. \rangle \}$ be a full Hilbert $A$-module. Then any bijective bounded module morphism $T$, for which every…

Operator Algebras · Mathematics 2026-04-09 Michael Frank

These are lecture notes for five lectures given at MPI Leipzig in May 2024. We study the moduli space M_{0,n} of n distinct points on P^1 as a positive geometry and a binary geometry. We develop mathematical formalism to study…

Algebraic Geometry · Mathematics 2025-05-28 Thomas Lam

A $\Sigma^*$-algebra is a concrete $C^*$-algebra that is sequentially closed in the weak operator topology. We study an appropriate class of $C^*$-modules over $\Sigma^*$-algebras analogous to the class of $W^*$-modules (selfdual…

Operator Algebras · Mathematics 2016-09-13 Clifford A. Bearden

It is well known that "bad" quotient spaces (typically: non-Hausdorff) can be studied by associating to them the groupoid C*-algebra of an equivalence relation, that in the "nice" cases is Morita equivalent to the C*-algebra of continuous…

Operator Algebras · Mathematics 2022-07-13 Francesco D'Andrea , Giovanni Landi , Fedele Lizzi

We consider a fractional Schr\"odinger-Poisson system in the whole space $\mathbb R^{N}$ in presence of a positive potential and depending on a small positive parameter $\varepsilon.$ We show that, for suitably small $\varepsilon$ (i.e. in…

Analysis of PDEs · Mathematics 2016-01-05 Edwin G. Murcia , Gaetano Siciliano

We characterize bounded and compact positive Toeplitz operators defined on the Bergman spaces over the Siegel upper half-space.

Complex Variables · Mathematics 2019-04-02 Congwen Liu , Jiajia Si

The operator space analogue of the {\em strong form} of the principle of local reflexivity is shown to hold for any von Neumann algebra predual, and thus for any $C^{*}$-algebraic dual. This is in striking contrast to the situation for…

Operator Algebras · Mathematics 2007-05-23 Edward G. Effros , Marius Junge , Zhong-Jin Ruan