10 papers
Norm of infinite doubly stochastic matrices
Ludovick Bouthat, Javad Mashreghi, Raphaël Vo
In finite dimensions, every doubly stochastic matrix has the -operator norm equal to for all . However, in the infinite-dimensional setting, this pr…
Oppenheim--Schur inequalities for causal products
Dominique Guillot, Javad Mashreghi, Prateek Kumar Vishwakarma
We establish a class of Oppenheim--Schur-type inequalities for the convolutional Jury product of positive semidefinite matrices. These results extend to a causal convolutional sett…
The conjugate orbit of a unitary operator
Javad Mashreghi, Marek Ptak, William T. Ross
This paper discusses various aspects of the collection of unitary operators , where is a fixed unitary operator on a complex Hilbert space and varies ove…
Sharp lower bounds for generalized operator products
Dominique Guillot, Javad Mashreghi, Prateek Kumar Vishwakarma
We consider general bilinear products defined by positive semidefinite matrices. Typically non-commutative, non-associative, and non-unital, these products preserve positivity and…
Functional Calculi, Positivity, and Convolution of Matrices
Javad Mashreghi, Mostafa Nasri, Prateek Kumar Vishwakarma
Convolution admits a natural formulation as a functional operation on matrices. Motivated by the functional and entrywise calculi, this leads to a framework in which convolution de…
Weighted composition operators on de Branges-Rovnyak spaces
Emmanuel Fricain, Muath Karaki, Javad Mashreghi +1
In this paper, we characterize the boundedness and the compactness of weighted composition operators acting on a de Branges-Rovnyak space , where the symbol is a…
Infinitely supported harmonically weighted Dirichlet spaces which are de Branges Rovnyak spaces
Carlo Bellavita, Eugenio Dellepiane, Andreas Hartmann +1
Harmonically weighted Dirichlet spaces and de Branges_Rovnyak spaces are two fundamental structures in analytic function theory exhibiting rich and…
Schauder Basis with Finite Blaschke Products
Emmanuel Fricain, Javad Mashreghi, Mostafa Nasri +1
We construct a Schauder basis for the space , the space of holomorphic functions on the closed unit disk, consisting entirely of finite Blaschke products. The expan…
The spectral analysis of the difference quotient operator on model spaces
Carlo Bellavita, Eugenio Alberto Dellepiane, Javad Mashreghi
We conduct a spectral analysis of the difference quotient operator , associated with a boundary point , on the model space . We describe the o…
The Cesàro operator on local Dirichlet spaces
Eugenio Dellepiane, Javad Mashreghi, Mostafa Nasri +1
The family of Cesàro operators , and , consists of finite rank operators on Banach spaces of analytic functions on the open unit disc. In this work, w…