K. Hedayatian

ORCID: 0000-0002-5754-4661
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Research Areas
  • Holomorphic and Operator Theory
  • Advanced Topics in Algebra
  • Algebraic and Geometric Analysis
  • Advanced Banach Space Theory
  • Spectral Theory in Mathematical Physics
  • Matrix Theory and Algorithms
  • Analytic and geometric function theory
  • Advanced Operator Algebra Research
  • Approximation Theory and Sequence Spaces
  • Advanced Harmonic Analysis Research
  • Advanced Topology and Set Theory
  • Meromorphic and Entire Functions
  • Computability, Logic, AI Algorithms
  • Advanced Differential Equations and Dynamical Systems
  • Advanced Algebra and Logic
  • Differential Equations and Boundary Problems
  • Iterative Methods for Nonlinear Equations
  • Advanced Algebra and Geometry
  • Fixed Point Theorems Analysis
  • Mathematical Analysis and Transform Methods
  • advanced mathematical theories
  • Mathematical Inequalities and Applications
  • Heat Transfer and Numerical Methods
  • Advanced Optimization Algorithms Research
  • Rings, Modules, and Algebras

Shiraz University
2011-2024

Institute for Research in Fundamental Sciences
2004-2007

10.1216/rmj-2012-42-1-15 article EN other-oa Rocky Mountain Journal of Mathematics 2012-01-23

We give sufficient conditions under which a weighted composition operator on Hilbert space of analytic functions is not weakly supercyclic. Also, we some necessary and for hypercyclicity supercyclicity operators the open unit disc.

10.1155/2010/143808 article EN cc-by Abstract and Applied Analysis 2010-01-01

For a positive integer m, bounded linear operator T on Hilbert space H is called an m-isometry, ifWe characterize all misometric unilateral weighted shift operators that are not m -1-isometries in terms of their weight sequences.Then we prove the reflexivity some classes operators: (1) All nonnegative powers m-isometric shifts.(2) The contractions whose spectrum closed unit disc.(3) non-negative hyponormal m-isometries. Introduction.Let be complex separable H, Lat lattice subspaces which...

10.1216/rmj-2013-43-1-123 article EN other-oa Rocky Mountain Journal of Mathematics 2013-02-01

Suppose that X is a separable normed space and the operators A Q are bounded on . In this paper, it shown if = , an isometry, nilpotent then operator + neither supercyclic nor weakly hypercyclic. Moreover, underlying Hilbert co‐isometric operator, we give sufficient conditions under which satisfies supercyclicity criterion.

10.1155/2011/686832 article EN cc-by Abstract and Applied Analysis 2011-01-01

By the well-known result of Yood, every strictly transitive algebra operators on a Banach space is WOT-dense. This motivated us to investigate relationships between SOT and WOT largeness sets transitivity behavior them. We show that, obtain Yood's result, strict may not be replaced by weaker condition hypertransitivity. prove for wide class topological vector spaces, SOT-dense set hypertransitive. The general form that are presented. also describe WOT-dense It shown hypertransitive if only...

10.3906/mat-1508-87 article EN TURKISH JOURNAL OF MATHEMATICS 2018-01-01

An n-tuple of commuting operators, (T_1,T_2,...,T_n) on a Hilbert space \cal H is said to be hypercyclic, if there exists vector x \in such that the set {T_1^{k_1} T_2^{k_2}... T_n^{k_n}x : k_i \geq 0, i=1,2,...n} dense in H. In this paper, we give sufficient conditions under which adjoint an weighted composition operator analytic functions hypercyclic.

10.3906/mat-1010-402 article EN TURKISH JOURNAL OF MATHEMATICS 2012-01-01

10.1007/s40995-017-0325-7 article EN Iranian Journal of Science and Technology Transactions A Science 2017-12-18

Let $\{\beta(n)\}$ be a sequence of positive numbers with $\beta(0) = 1$ and let $p\gt 0$. By the space $H^{p}(\beta)$, we mean set all formal power series $\sum^{\infty}_{n=0} \hat{f}(n) z^{n}$ for which |\hat{f}(n)|^{p} \beta(n)^{p} \lt \infty$. In this paper, study cyclic vectors forward shift operator supercyclic backward on $H^{p} (\beta)$.

10.11650/twjm/1500407663 article EN Taiwanese Journal of Mathematics 2004-09-01

10.1016/j.laa.2019.11.009 article EN publisher-specific-oa Linear Algebra and its Applications 2019-11-15

A commuting $d$-tuple $T=(T_{1}, \ldots , T_{d})$ of bounded linear operators on a Hilbert space $\mathcal {H}$ is called spherical $m$-isometry if $\sum _{j=0}^{m}(-1)^{j}\binom {m}{j}Q_{T}^{j}(I)=0$, where $I$ denotes the identity operator and $Q_{T}(A)=\sum _{i=1}^{d}T_{i}^{*}AT_{i}$ for every $A$ {H}$. Also, $T$ toral _{p\in \mathbb {N}^{d},\, 0\leq p\leq n}(-1)^{\vert p\vert }\binom {n}{p}{T^{\ast }}^{p}T^{p}=0 $ all $n\in {N}^{d}$ with $\vert n\vert = m$. The present paper mainly...

10.1216/rmj-2019-49-1-283 article EN Rocky Mountain Journal of Mathematics 2019-02-01

10.1007/s40840-014-0083-z article EN Bulletin of the Malaysian Mathematical Sciences Society 2014-12-16

An A-m-isometric operator is a bounded linear T on Hilbert space <TEX>$\mathcal{H}$</TEX> satisfying <TEX>$\sum\limits_{k=0}^{m}(-1)^{m-k}T^{*^k}AT^k=0$</TEX>, where A positive operator. We give sufficient conditions under which A-m-isometries are not N-supercyclic, for every <TEX>$N{\geq}1$</TEX>; that is, there subspace E of dimension N such its orbit dense in <TEX>$\mathcal{H}$</TEX>.

10.5831/hmj.2015.37.3.281 article EN Honam Mathematical Journal 2015-09-25

Let M_z and B denote, respectively, the multiplication operator backward shift on a weighted Hardy space. We present sufficient conditions so that M_{z^n} is similar to \bigoplus_1^nM_z, B^n \bigoplus_1^nB. The first part generalizes result obtained by Yucheng Li.

10.3906/mat-1103-7 article EN TURKISH JOURNAL OF MATHEMATICS 2012-01-01

10.1016/s0252-9602(10)60107-5 article EN Acta Mathematica Scientia 2010-07-01

A bounded linear operator T on a Hilbert space ℋ , satisfying for every h ∈ is called convex operator. In this paper, we give necessary and sufficient conditions under which composition large class of weighted Hardy spaces an isometry. Also, discuss convexity multiplication operators.

10.1155/2009/931020 article EN cc-by Abstract and Applied Analysis 2009-01-01

A bounded linear operator T on a Hilbert space H is an (m, p) -isometry ifand m 1 .In this paper, two significant results will be proved.First, we introduce some perturbations of -isometries which are (n, for suitable n .Indeed, show that the sum and commuting nilpotent degree r (prp + m, every even number p .As application, second result to prove such operators not N -supercyclic any positive integer , if rational number.These generalize previous works -isometries.

10.7153/oam-11-26 article EN Operators and Matrices 2017-01-01

A bounded linear operator $T$ on a Hilbert space is an isometric $N$-Jordan if it can be written as $A+Q$, where $A$ isometry and $Q$ nilpotent of order $N$ such that $AQ= QA$. In this paper, we will show the only weighted shift operators are isometries. This answers question recently raised.

10.3906/mat-1507-54 article EN TURKISH JOURNAL OF MATHEMATICS 2016-01-01

Suppose that the multiplication operator by independent variable z, M z , acting on Banach spaces of formal Laurent series is invertible. We will use a result Hadwin and Nordgren to show reflexive. This improves recently obtained.

10.1142/s0129167x07004114 article EN International Journal of Mathematics 2007-03-01

We present a non-weak supercyclicity criterion for vectors in infinite dimensional Banach spaces. Also, we give sufficient conditions under which class of weighted composition operators on space analytic functions is not weakly supercyclic. In particular, show that the semigroup linear isometries spaces $S^p$ ($p>1$), Moreover, observe every operator some such as disc algebra or Lipschitz

10.36045/bbms/1503453707 article EN Bulletin of the Belgian Mathematical Society - Simon Stevin 2017-04-01

Using Banach algebra structure of the Hardy space, we describe all finite codimensional invariant subspaces a cyclic convolution operator on space $H^p$ unit disc for $1 \leq p \infty$. We also observe that every in commutant such operators is not weakly supercyclic.

10.36045/bbms/1432840865 article EN Bulletin of the Belgian Mathematical Society - Simon Stevin 2015-05-01

10.1016/j.jmaa.2023.127015 article EN Journal of Mathematical Analysis and Applications 2023-01-10

In this note it is shown that there a bounded linear operator T on the Hardy Hilbert space H2 and vector f in such closure of set {αTnf:α∈ℂ,n≥0} not H2, but for every subsequence (nk)k=1∞ closed span {Tnkf:k≥1} whole H2. Furthermore, {Tng:n≥0} some g∈H2.

10.1016/j.exco.2023.100131 article EN cc-by Examples and Counterexamples 2024-01-12

Let H be a separable complex Hilbert space. A commuting tuple <TEX>$T=(T_1,{\cdots},T_n)$</TEX> of bounded linear operators on is called spherical isometry if <TEX>$\sum_{i=1}^{n}T^*_iT_i=I$</TEX>. The T toral each <TEX>$T_i$</TEX> an isometry. In this paper, we show that for <TEX>$n{\geq}1$</TEX> there supercyclic n-tuple isometries <TEX>$\mathbb{C}^n$</TEX> and no or isometric infinite-dimensional

10.4134/bkms.2015.52.5.1481 article EN Bulletin of the Korean Mathematical Society 2015-09-30

We characterize the commutants of some multiplication operators on a Banach space analytic functions defined bounded domain in plane. Under certain conditions symbol operator, we show that its commutant is set operators. This partially answers question Axler, Cuckovic and Rao. Next, hyper-reflexivity these are proved. The paper concluded by proving with symbols \varphi (z) = z^k, k=1, 2,... .

10.3906/mat-1101-89 article EN TURKISH JOURNAL OF MATHEMATICS 2013-01-01
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