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We give necessary and sufficient condition so that we have d-hypercyclicity for operators who map a holomorphic function to a partial sum of the Taylor expansion. This problem is connected with doubly universal Taylors series and this is an…

Complex Variables · Mathematics 2015-04-02 Vagia Vlachou

We consider an integral operator $\mathcal{I}$, special instances of which was studied in various contexts. Using an appropriate transformation we write this operator in terms of weighted composition operators. Then, we provide a…

Complex Variables · Mathematics 2012-04-16 Epaminondas Diamantopoulos

In this paper, we study Birkhoff-James orthogonality of bounded linear operators and give a complete characterization of Birkhoff-James orthogonality of bounded linear operators on infinite dimensional real normed linear spaces. As an…

Functional Analysis · Mathematics 2024-08-13 Debmalya Sain , Kallol Paul , Arpita Mal

We give sharp regularity conditions, ensuring the backward uniquess property to a class of parabolic operators.

Analysis of PDEs · Mathematics 2007-05-23 Daniele Del Santo , Martino Prizzi

In this paper we define $\lambda$-hyponormal operators on an infinite dimensional Hilbert space $\mathcal{H}$ and find a class of $\lambda$-hyponormal operators that can not be hypercyclic. Also, we study closedness of range and…

Functional Analysis · Mathematics 2025-08-07 Y. Estaremi , M. S. Al Ghafri , and S. Shamsigamchi

We provide a brief survey of a certain algebra of operators on symmetric polynomials, and collect a number of previously known results in the field.

Combinatorics · Mathematics 2013-10-15 Andrei Negut

We discuss some properties of conditional expectation operators, and use these facts to prove an interesting counterexample regarding sufficient statistics. In particular, we show that there exists sufficient random variables X and Y, such…

Statistics Theory · Mathematics 2011-07-05 Andrew Tausz

It is shown that a contraction on a Hilbert space is complex symmetric if and only if the values of its characteristic function are all symmetric with respect to a fixed conjugation. Applications are given to the description of complex…

Functional Analysis · Mathematics 2007-05-23 Nicolas Chevrot , Emmanuel Fricain , Dan Timotin

Let $x=a+ib$ be a complex number, so we have the following inequality $$(1/\sqrt{2})|a+b|\leq |x|\leq |a|+|b|$$ We give an operator version of above inequality. Also we obtain some results for normal operators.

Functional Analysis · Mathematics 2015-12-08 Ali Taghavi , Vahid Darvish

Voltage operations extend traditional geometric and combinatorial operations (such as medial, truncation, prism, and pyramid over a polytope) to operations on maniplexes, maps, polytopes, and hypertopes. In classical operations, the…

Combinatorics · Mathematics 2023-12-21 Isabel Hubard , Elías Mochán , Antonio Montero

We study the most general continuous transformation on the generators of bilinear master equations of a quantum oscillator. We find that transformation operators that preserve the hermiticity of density operators and conserve the…

Quantum Physics · Physics 2017-02-23 B. A. Tay

We prove several sharp weighted norm inequalities for commutators of classical operators in harmonic analysis. We find sufficient $A_p$-bump conditions on pairs of weights $(u,v)$ such that $[b,T]$, $b\in BMO$ and $T$ a singular integral…

Classical Analysis and ODEs · Mathematics 2011-09-14 David Cruz-Uribe , Kabe Moen

In this work, generalized hypergeometric functions for bicomplex argument is introduced and its convergence criteria is derived. Furthermore, integral representation of this function has been established. Moreover, quadratic transformation,…

Complex Variables · Mathematics 2025-04-08 Snehasis Bera , Sourav Das , Abhijit Banerjee

Two Bessel sequences are orthogonal if the composition of the synthesis operator of one sequence with the analysis operator of the other sequence is the 0 operator. We characterize when two Bessel sequences are orthogonal when the Bessel…

Functional Analysis · Mathematics 2007-05-23 Eric Weber

We study weighted composition operators on Hilbert spaces of analytic functions on the unit ball with kernels of the form $(1-<z,w>)^{-\gamma}$ for $\gamma>0$. We find necessary and sufficient conditions for the adjoint of a weighted…

Functional Analysis · Mathematics 2012-07-26 Trieu Le

A theorem that is of aid in computing the domain of the adjoint operator is provided. It may serve e.g. as a criterion for selfadjointness of a symmetric operator, for normality of a formally normal operator or for $H$--selfadjointness of…

Functional Analysis · Mathematics 2011-06-13 Michal Wojtylak

We identify conditions giving large natural classes of partial differential operators for which it is possible to construct a complete set of Laplace invariants. In order to do that we investigate general properties of differential…

Mathematical Physics · Physics 2020-12-22 David Hobby , Ekaterina Shemyakova

We study the properties of shifted vertex operator algebras, which are vertex algebras derived from a given theory by shifting the conformal vector. In this way, we are able to exhibit large numbers of vertex operator algebras which are…

Quantum Algebra · Mathematics 2007-05-23 Chongying Dong , Geoffrey Mason

This article is devoted to the construction of pseudomodes of one-dimensional biharmonic operators with the complex-valued potentials via the WKB method. As a by-product, the shape of pseudospectrum near infinity can be described. This is a…

Spectral Theory · Mathematics 2022-01-11 Tho Nguyen Duc

Let $A$ and $B$ be two -non necessarily bounded- normal operators. We give new conditions making their product normal. We also generalize a result by Deutsch et al on normal products of matrices.

Functional Analysis · Mathematics 2012-05-28 Mohammed Hichem Mortad , Khaldia Madani