Zobrazeno 1 - 10
of 13
pro vyhledávání: '"Georgios Katsouleas"'
Publikováno v:
Mathematics, Vol 9, Iss 15, p 1729 (2021)
In this note, given a matrix A∈Cn×n (or a general matrix polynomial P(z), z∈C) and an arbitrary scalar λ0∈C, we show how to define a sequence μkk∈N which converges to some element of its spectrum. The scalar λ0 serves as initial term (μ0
Externí odkaz:
https://doaj.org/article/57b2dc91a25e4eeda30745c3369ac08f
Autor:
Georgios Katsouleas, John Maroulas
Publikováno v:
Opuscula Mathematica, Vol 33, Iss 2, Pp 307-321 (2013)
In this paper we consider Rellich's diagonalization theorem for analytic self-adjoint operator functions and investigate variational principles for their eigenfunctions and interlacing statements. As an application, we present a characterization for
Externí odkaz:
https://doaj.org/article/b2b85cfcb4434f90a7583c9714718bec
Publikováno v:
The Electronic Journal of Linear Algebra. :32-48
The Birkhoff-James $\varepsilon$-sets of vectors and vector-valued polynomials (in one complex variable) have recently been introduced as natural generalizations of the standard numerical range of (square) matrices or operators and matrix or operator
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::1a3b14767a92f3d76936b42ede785c7c
https://doi.org/10.13001/ela.2022.6561
https://doi.org/10.13001/ela.2022.6561
Publikováno v:
Mathematics
Volume 9
Issue 15
Mathematics, Vol 9, Iss 1729, p 1729 (2021)
Volume 9
Issue 15
Mathematics, Vol 9, Iss 1729, p 1729 (2021)
In this note, given a matrix A∈Cn×n (or a general matrix polynomial P(z), z∈C) and an arbitrary scalar λ0∈C, we show how to define a sequence μkk∈N which converges to some element of its spectrum. The scalar λ0 serves as initial term (μ0
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6f385d1f6c5cee2a9159e0a50c9b5f85
In this work, we analyze an unfitted discontinuous Galerkin discretization for the numerical solution of the Stokes system based on equal higher-order discontinuous velocities and pressures. This approach combines the best from both worlds, firstly t
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1c2436f1dcf5811e25850284639de427
Publikováno v:
Economic and Financial Challenges for Eastern Europe ISBN: 9783030121686
Stock price analysis is one of the most important issues concerning investments and financial decision-making. Thus, stock price analysis and estimation models can be very useful in the estimation of a firm’s financial development. The aim of this
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::dcdfe90c0b782bacfc619a270739d6e5
https://doi.org/10.1007/978-3-030-12169-3_23
https://doi.org/10.1007/978-3-030-12169-3_23
Autor:
Georgios Katsouleas, John Maroulas
Publikováno v:
The Electronic Journal of Linear Algebra. 31:244-262
A pair of matrices is said to be imbeddable precisely when one is an isometric projection of the other on a suitable subspace. The concept of imbedding has been the subject of extensive study. Particular emphasis has been placed on relating the spect
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::77511eb513634a1ab44acfdcff8f96c5
https://doi.org/10.13001/1081-3810.2832
https://doi.org/10.13001/1081-3810.2832
Autor:
Georgios Katsouleas, John Maroulas
Publikováno v:
SIAM Journal on Matrix Analysis and Applications. 37:1022-1037
For an $n \times n$ matrix $A$ and an integer $k \in [1,n]$, the concept of the higher rank numerical range $\Lambda_k(A)=\left\{z \in \mathbb{C}:V^*AV=zI_k, \; V \in \mathbb{C}^{n \times k}, \; V^*V=I_k\right\}$ has been introduced in relation to th
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::7bd5dc8c9b180c0f2e470dda4cd3ab32
https://doi.org/10.1137/15m1009342
https://doi.org/10.1137/15m1009342
Autor:
Georgios Katsouleas, John Maroulas
Publikováno v:
Applied Mathematics and Computation. 233:557-564
For several applications, it is highly desirable to understand how the eigenvalues of an imbeddable matrix V ∗ AV , where V ∈ C n × k is an isometry, are distributed throughout the numerical range of A ∈ C n × n . There has been extensive stu
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::f10c72fbc490a89533f45941f2ddd6c6
https://doi.org/10.1016/j.amc.2014.02.016
https://doi.org/10.1016/j.amc.2014.02.016
Autor:
Georgios Katsouleas, John Maroulas
Publikováno v:
Linear Algebra and its Applications. 439:552-564
Let w(A) be the numerical range of a matrix A ∈ C n × n and a set of points μ 1 , … , μ n - k ∈ w ( A ) that define the spectrum σ ( B ) of a matrix B ∈ C ( n - k ) × ( n - k ) . The problem of imbedding concerns the existence and constr
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::21f22547b5b7331e51ee016e96cbd28c
https://doi.org/10.1016/j.laa.2013.03.013
https://doi.org/10.1016/j.laa.2013.03.013