Results 11 to 20 of about 165,123,802 (106)

System of Non-Linear Volterra Integral Equations in a Direct-Sum of Hilbert Spaces

open access: yesJournal of Nigerian Society of Physical Sciences, 2022
We use the contraction mapping theorem to present the existence and uniqueness of solutions in a short time to a system of non-linear Volterra integral equations in a certain type of direct-sum H[a; b] of a Hilbert space V[a; b].
Jabar Hassan   +2 more
doaj   +2 more sources

Khatri-Rao Products for Operator Matrices Acting on the Direct Sum of Hilbert Spaces [PDF]

open access: yesJournal of Mathematics, 2016
We introduce the notion of Khatri-Rao product for operator matrices acting on the direct sum of Hilbert spaces. This notion generalizes the tensor product and Hadamard product of operators and the Khatri-Rao product of matrices.
Arnon Ploymukda, Pattrawut Chansangiam
doaj   +3 more sources

Inequalities for sums and direct sums of Hilbert space operators

open access: yesLinear Algebra and its Applications, 2007
The authors investigate several singular value inequalities and norm inequalities involving sums and direct sums of operators. They prove the following nice Cauchy--Schwarz type inequality for singular values: \[ s_j \left(\sum_{i=1}^n A_iX_iB_i\right) \leq \left\| \sum_{i=1}^n| A_i^*| ^2\right\| ^{1/2} \left\| \sum_{i=1}^n| B_i| ^2\right\| ^{1/2} s_j ...
Hirzallah, Omar, Kittaneh, Fuad
openaire   +3 more sources

Homomorphisms and direct sums of nested Hilbert spaces [PDF]

open access: yesCommunications in Mathematical Physics, 1967
We prove some elementary facts about homomorphisms and infinite direct sums of nested Hilbert spaces.
Alex Grossmann
openaire   +4 more sources

A spectral theory for certain operators on a direct sum of Hilbert spaces

open access: yesMathematische Annalen, 1966
Let ℌ p = v ⊕ ... ⊕ ℌ be the direct sum of the Hilbert space ℌ with itself p times. Linear maps y = Ax in ℌ p have the form y i = Σ a ij x i where a ij are linear maps in ℌ and there are many natural problems concerned with the discovery of those properties, enjoyed by the operators a ij , that are shared by the operator A.
Nelson Dunford
exaly   +5 more sources

Fusion frames and g-frames in tensor product and direct sum of Hilbert spaces

open access: yesApplicable Analysis and Discrete Mathematics, 2012
In this paper we study fusion frames and g-frames for the tensor products and direct sums of Hilbert spaces. We show that the tensor product of a finite number of g-frames (resp. fusion frames, g-Riesz bases) is a g-frame (resp. fusion frame, g-Riesz basis) for the tensor product space and vice versa.
Amir Khosravi, Azandaryani Mirzaee
openaire   +4 more sources

Vector inequalities for powers of some operators in Hilbert spaces [PDF]

open access: yes, 2008
Vector inequalities for powers of some operators in Hilbert spaces with applications for operator norm, numerical radius, commutators and self-commutators are ...
Dragomir, Sever S, S.S. Dragomir
core   +7 more sources

Ternary structures in Hilbert spaces [PDF]

open access: yes, 2011
PhDTernary structures in Hilbert spaces arose in the study of in nite dimensional manifolds in di erential geometry. In this thesis, we develop a structure theory of Hilbert ternary algebras and Jordan Hilbert triples which are Hilbert spaces equipped
Bahmani, Fatemeh
core   +4 more sources

Gap Between Operator Norm and Spectral Radius for the Square of Antidiagonal Block Operator Matrices

open access: yesCommunications in Advanced Mathematical Sciences, 2022
In this work, the gap between operator norm and spectral radius for the square of antidiagonal block operator matrices in the direct sum of Banach spaces has been investigated, and also the gap between operator norm and numerical radius for the square of
Elif Otkun Çevik
doaj   +1 more source

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