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Commutators of a large class of bilinear operators and multiplication by functions in a certain subspace of the space of functions of bounded mean oscillations are shown to be jointly compact. Under a similar commutation, fractional…

Classical Analysis and ODEs · Mathematics 2013-10-16 Árpád Bényi , Wendolín Damián , Kabe Moen , Rodolfo H. Torres

We study some basic properties of the class of universal operators on Hilbert space, and provide new examples of universal operators and universal pairs.

Functional Analysis · Mathematics 2017-02-20 Riikka Schroderus , Hans-Olav Tylli

We study groups of isometries on non-alternating symmetric bilinear forms on vector spaces of characteristic two, and actions of these groups on exterior powers of the space, viewed as modules over algebras generated by Hodge operators.

Group Theory · Mathematics 2025-09-19 Linus Kramer , Markus J. Stroppel

Using the bicomplex numbers $\mathbb{T}$ which is a commutative ring with zero divisors defined by $\mathbb{T}=\{w_0 + w_1 i_1 + w_2 i_2 + w_3 j | w_0, w_1, w_2, w_3 \in \mathbb{R}\}$ where $i_{1}^{2} = -1, i_{2}^{2} = -1, j^2 = 1, i_1 i_2…

Quantum Physics · Physics 2013-07-10 Dominic Rochon , Sebastien Tremblay

Quasi-isometric liftings similar to isometries, for the operators similar to contractions in Hilbert spaces, are investigated. The existence of such liftings is established, and their applications are explored for specific operator classes,…

Functional Analysis · Mathematics 2025-01-27 Laurian Suciu , Andra-Maria Stoica

We characterize the pairs of operator spaces which occur as pairs of Morita equivalence bimodules between non-selfadjoint operator algebras in terms of the mutual relation between the spaces. We obtain a characterization of the operator…

Operator Algebras · Mathematics 2007-05-23 I. G. Todorov

We give a generalization of the Hodge operator to spaces $(V,h)$ endowed with a hermitian or symmetric bilinear form $h$ over arbitrary fields, including the characteristic two case. Suitable exterior powers of $V$ become free modules over…

Group Theory · Mathematics 2024-10-15 Linus Kramer , Markus J. Stroppel

We construct a family of bilinear differential operators which satisfy certain gauge properties. These operators can be naturally associated with $q$-deformations of classical integrable hierarchies. In particular, we consider the case when…

Exactly Solvable and Integrable Systems · Physics 2016-08-04 Dmitri Noshchenko

A weighted composition operator on a reproducing kernel Hilbert space is given by a composition, followed by a multiplication. We study unitary and co-isometric weighted composition operators on unitarily invariant spaces on the Euclidean…

Functional Analysis · Mathematics 2025-12-23 Michael Hartz , Maximilian Tornes

In this paper, we study the linear dynamical properties of shift operators on some classes of Segal algebras. Moreover, we characterize hypercyclic generalized bilateral shift operators on the standard Hilbert module.

Functional Analysis · Mathematics 2023-06-22 Stefan Ivkovic , Seyyed Mohammad Tabatabaie

In this paper, we describe necessary and sufficient conditions for a binormal or complex symmetric operator to have the other property. Along the way, we find connections to the Duggal and Aluthge transforms, and give further properties of…

Functional Analysis · Mathematics 2017-05-16 Caleb Holleman , Thaddeus McClatchey , Derek Thompson

In this paper we construct a large class of multiplication operators on reproducing kernel Hilbert spaces which are {\em homogeneous} with respect to the action of the M\"{o}bius group consisting of bi-holomorphic automorphisms of the unit…

Functional Analysis · Mathematics 2016-08-16 Adam Korányi , Gadadhar Misra

A complete characterization of the similarity between two operator-valued multishifts with invertible operator weights is obtained purely in terms of operator weights. This generalizes several existing results of the unitary equivalence of…

Functional Analysis · Mathematics 2024-01-23 Soumitra Ghara , Surjit Kumar , Shailesh Trivedi

Let $(S_1, S_2)$ be a bi-isometry, that is, a pair of commuting isometries $S_1$ and $S_2$ on a complex Hilbert space $\mathscr H.$ By the von Neumann-Wold decomposition, the hyper-range $\mathscr H_\infty(S_1):=\cap_{n=0}^\infty…

Functional Analysis · Mathematics 2023-02-13 Sameer Chavan , Md. Ramiz Reza

We study the microlocal properties of bisingular operators, a class of operators on the product of two compact manifolds. We define a wave front set for such operators, and analyse its properties. We compare our wave front set with the $SG$…

Functional Analysis · Mathematics 2014-03-03 M. Borsero , R. Schulz

Every unital nonselfadjoint operator algebra possesses canonical and functorial classes of faithful (even completely isometric) Hilbert space representations satisfying a double commutant theorem generalizing von Neumann's classical result.…

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

We define the domain of a linear fractional transformation in a space of operators and show that both the affine automorphisms and the compositions of symmetries act transitively on these domains. Further, we show that Liouville's theorem…

Complex Variables · Mathematics 2009-09-25 Lawrence A. Harris

The possibility of defining sesquilinear forms starting from one or two sequences of elements of a Hilbert space is investigated. One can associate operators to these forms and in particular look for conditions to apply representation…

Functional Analysis · Mathematics 2023-10-31 Rosario Corso

Given two C*-algebras A and B, abstract A-B bimodules that can be isometrically represented as operator bimodules are characterised in terms of their norm. Various properties of such bimodules are given. Their theory is very similar to…

Operator Algebras · Mathematics 2007-05-23 C. Pop

We study the typical behavior of bounded linear operators on infinite dimensional complex separable Hilbert spaces in the norm, strong-star, strong, weak polynomial and weak topologies. In particular, we investigate typical spectral…

Functional Analysis · Mathematics 2014-05-01 Tanja Eisner , Tamas Matrai