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Bahmann Yousefi

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Academic Degrees:
I) Assistant Professor of Mathematics, Shiraz University, Iran, 1992.
II) Associate Professor of Mathematics, Shiraz University, Iran, 2000.
III) Full Professor of Mathematics, Shiraz University, Iran, 2004.
Teaching at:
1. Shiraz University, 2. Estahban Azad University, 3. Azad University Science and Research Branch, 4. Shiraz Payame Noor University.
University education:
i) B.S. (Applied Mathematics, field of Computational Science & Numerical Analysis), Shiraz University, Iran, 1987.
ii) M.S. (Mathematics, field of Mathematical Analysis), Shiraz University, Iran, 1989.
iii) Ph.D. (Mathematics, field of Operator Theory and Functional Analysis), Shiraz University, Iran, 1992.

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Teresa Bermúdez

Sahand Communications in Mathematical Analysis

University of margheh

Mohammadreza Azimi

University of margheh

SUNY: Potsdam

Abdeslam El Bakkali

Rodrigo Cardeccia

Universidad Pablo de Olavide

Parviz Sadat Hosseini

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Papers by Bahmann Yousefi

Invertible Subspace Hypercyclic Operators

Journal of Mathematical Extension, Jun 28, 2015

The purpose of the present paper is to treat a notion, which can be viewed as a localization of t... more

A class of new results in FLM algebras

Communications in Mathematical Analysis, 2019

In this paper, we first derive some results by using the Gelfand spectrum and spectrum in FLM alg... more

Continuity in Fundamental Locally Multiplicative Topological Algebras

International Journal of Nonlinear Analysis and Applications, 2021

Abstract. In this paper, we first derive specific results concerning the continuity and upper sem... more Abstract. In this paper, we first derive specific results concerning the continuity and upper semi-continuity of the spectral radius and spectrum functions on fundamental locally multiplicative topological algebras. We continue our investigation by further determining the automatic continuity of linear mappings and homomorphisms in these algebras.

Cyclic Vector of the Weighted Mean Matrix Operator

In this paper, we first prove cyclicity of bounded diagonal matrix on H p (β) and we provide some... more In this paper, we first prove cyclicity of bounded diagonal matrix on H p (β) and we provide some conditions for a weighted mean matrix operator to have eigenvectors. Then we study boundedness of matrix of eigenvectors, diagonalization and cyclicity of the weighted mean matrix operator on the weighted Hardy spaces.

On a Fixed Point Iteration Procedure

Let (X,d) be a cone metric space and T be a self-map of X. In this paper we investigate the conve... more

Multiple Weighted Composition Operators and

In this paper we give some sufficient conditions for the adjoint of the multiple weighted composi... more

Subspace-Countably Hypercyclicity Criterion for Tuples of Operators

International journal of pure and applied mathematics, 2015

In this paper, we give a criterion under which a tuple being count- ably subspace-hypercyclic.

Subspace Transitivity and Subspace Supercyclicity of Tuples of Operators in SOT and in the norm of Hilbert-Schmidt operators

Journal of Mathematical Extension, 2017

In this paper, we investigate the subspace transitivity and subspace supercyclicity of tuples of ... more

Supercyclicity of Multiple Weighted Composition Operators

In this paper we give some sufficient conditions for the adjoint of the multiple weighted composi... more

Invertible Subspace-Hypercyclic Operators S . Talebi

A bounded linear operator on a Banach space X is called subspace-hypercyclic for a subspace M if ... more A bounded linear operator on a Banach space X is called subspace-hypercyclic for a subspace M if Orb(T, x) ∩ M is dense in M for a vector x ∈ M . In this paper we give conditions under which an operator is M -hypercyclic. Then by this result, we answer in the affirmative a question that recently raised by Madore and MartnezAvendano. AMS Subject Classification: 47A16; 47B37; 37B99

Tuples of Operators with Hereditarily Transitivity Property

Journal of Mathematical Extension, 2013

In this paper, we investigate the relation between hyper- cyclicity and d-dense orbits of a tuple... more

On the Banach Spaces of Formal Power Series

In this paper we characterize the dual space of formal power series and then we investigate cycli... more

The Australian Journal of Mathematical Analysis and Applications

In this paper, we introduce para-chaotic tuples of operators and we give some relations between p... more

On the Epsilon Hypercyclicity of a Pair of Operators

In this paper we prove that if a pair of operators is - hypercyclic for all >0, then it is top... more

A Condition of Reflexivity on some Sequence Spaces

In this paper we will give sucient conditions for the pow- ers of the multipliction operator Mz t... more

Tuples with Property of Cyclicity Criterions

In this paper we give conditions under which a tuple of operators satisfying the hypercyclicity, ... more

Hypercyclic and Compact Composition Operators on Banach Spaces of Formal Power Series

In this paper we consider the composition operator Cϕ acting between the weighted Hardy spaces H ... more In this paper we consider the composition operator Cϕ acting between the weighted Hardy spaces H p (β1) and H q (β2), for 1 <q ≤ p< ∞. We investigate the hypercyclicity of the composition operator Cϕ acting between weighted Hardy spaces in the unit disk. Furthermore, the characterization of the fixed points of the composition operator Cϕ will be considered.

eu SUBSPACE CRITERIONS OF TUPLES OF OPERATORS

In this paper, we introduce subspace hypercyclicity and transitivity of tuples of operators and w... more

On a Question of Allen Shields

Journal of Mathematical Extension, 2010

We give sufficient conditions for the boundedness of the analytic projection on the set of multip... more

Fixed points and compact weighted composition operators on Banach weighted Hardy spaces

Fixed Point Theory, Feb 1, 2018

We consider weighted composition operators C ψ,ϕ acting on Banach weighted Hardy spaces in the op... more We consider weighted composition operators C ψ,ϕ acting on Banach weighted Hardy spaces in the open unit disk such that the norms of the kernel functions for the appropriate order derivatives tend to infinity as one approaches the boundary. We investigate the relation between the compactness of C ψ,ϕ , the angular derivatives and the fixed points of ϕ, and we will see that compactness of C ψ,ϕ for some weight functions ψ forces ϕ to have a fixed point inside the open unit disk.

Invertible Subspace Hypercyclic Operators

Journal of Mathematical Extension, Jun 28, 2015

The purpose of the present paper is to treat a notion, which can be viewed as a localization of t... more

A class of new results in FLM algebras

Communications in Mathematical Analysis, 2019

In this paper, we first derive some results by using the Gelfand spectrum and spectrum in FLM alg... more

Continuity in Fundamental Locally Multiplicative Topological Algebras

International Journal of Nonlinear Analysis and Applications, 2021

Abstract. In this paper, we first derive specific results concerning the continuity and upper sem... more Abstract. In this paper, we first derive specific results concerning the continuity and upper semi-continuity of the spectral radius and spectrum functions on fundamental locally multiplicative topological algebras. We continue our investigation by further determining the automatic continuity of linear mappings and homomorphisms in these algebras.

Cyclic Vector of the Weighted Mean Matrix Operator

In this paper, we first prove cyclicity of bounded diagonal matrix on H p (β) and we provide some... more In this paper, we first prove cyclicity of bounded diagonal matrix on H p (β) and we provide some conditions for a weighted mean matrix operator to have eigenvectors. Then we study boundedness of matrix of eigenvectors, diagonalization and cyclicity of the weighted mean matrix operator on the weighted Hardy spaces.

On a Fixed Point Iteration Procedure

Let (X,d) be a cone metric space and T be a self-map of X. In this paper we investigate the conve... more

Multiple Weighted Composition Operators and

In this paper we give some sufficient conditions for the adjoint of the multiple weighted composi... more

Subspace-Countably Hypercyclicity Criterion for Tuples of Operators

International journal of pure and applied mathematics, 2015

In this paper, we give a criterion under which a tuple being count- ably subspace-hypercyclic.

Subspace Transitivity and Subspace Supercyclicity of Tuples of Operators in SOT and in the norm of Hilbert-Schmidt operators

Journal of Mathematical Extension, 2017

In this paper, we investigate the subspace transitivity and subspace supercyclicity of tuples of ... more

Supercyclicity of Multiple Weighted Composition Operators

In this paper we give some sufficient conditions for the adjoint of the multiple weighted composi... more

Invertible Subspace-Hypercyclic Operators S . Talebi

A bounded linear operator on a Banach space X is called subspace-hypercyclic for a subspace M if ... more A bounded linear operator on a Banach space X is called subspace-hypercyclic for a subspace M if Orb(T, x) ∩ M is dense in M for a vector x ∈ M . In this paper we give conditions under which an operator is M -hypercyclic. Then by this result, we answer in the affirmative a question that recently raised by Madore and MartnezAvendano. AMS Subject Classification: 47A16; 47B37; 37B99

Tuples of Operators with Hereditarily Transitivity Property

Journal of Mathematical Extension, 2013

In this paper, we investigate the relation between hyper- cyclicity and d-dense orbits of a tuple... more

On the Banach Spaces of Formal Power Series

In this paper we characterize the dual space of formal power series and then we investigate cycli... more

The Australian Journal of Mathematical Analysis and Applications

In this paper, we introduce para-chaotic tuples of operators and we give some relations between p... more

On the Epsilon Hypercyclicity of a Pair of Operators

In this paper we prove that if a pair of operators is - hypercyclic for all >0, then it is top... more

A Condition of Reflexivity on some Sequence Spaces

In this paper we will give sucient conditions for the pow- ers of the multipliction operator Mz t... more

Tuples with Property of Cyclicity Criterions

In this paper we give conditions under which a tuple of operators satisfying the hypercyclicity, ... more

Hypercyclic and Compact Composition Operators on Banach Spaces of Formal Power Series

In this paper we consider the composition operator Cϕ acting between the weighted Hardy spaces H ... more In this paper we consider the composition operator Cϕ acting between the weighted Hardy spaces H p (β1) and H q (β2), for 1 <q ≤ p< ∞. We investigate the hypercyclicity of the composition operator Cϕ acting between weighted Hardy spaces in the unit disk. Furthermore, the characterization of the fixed points of the composition operator Cϕ will be considered.

eu SUBSPACE CRITERIONS OF TUPLES OF OPERATORS

In this paper, we introduce subspace hypercyclicity and transitivity of tuples of operators and w... more

On a Question of Allen Shields

Journal of Mathematical Extension, 2010

We give sufficient conditions for the boundedness of the analytic projection on the set of multip... more

Fixed points and compact weighted composition operators on Banach weighted Hardy spaces

Fixed Point Theory, Feb 1, 2018

We consider weighted composition operators C ψ,ϕ acting on Banach weighted Hardy spaces in the op... more We consider weighted composition operators C ψ,ϕ acting on Banach weighted Hardy spaces in the open unit disk such that the norms of the kernel functions for the appropriate order derivatives tend to infinity as one approaches the boundary. We investigate the relation between the compactness of C ψ,ϕ , the angular derivatives and the fixed points of ϕ, and we will see that compactness of C ψ,ϕ for some weight functions ψ forces ϕ to have a fixed point inside the open unit disk.