Results 1 to 10 of about 28 (23)
The norm of an infinite L-matrix
Operators and Matrices, 2021 Evaluating the norm of infinite matrices, as operators acting on the sequence space 2 , is not an easy task. For a few celebrated matrices, e.g., the Hilbert matrix and the Cesàro matrix, the precise value of the norm is known.
Ludovick Bouthat, J. Mashreghi
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Alienation of Drygas’ and Cauchy’s Functional Equations
Annales Mathematicae Silesianae, 2021 Inspired by the papers [2, 10] we will study, on 2-divisible groups that need not be abelian, the alienation problem between Drygas’ and the exponential Cauchy functional equations, which is expressed by the equation f(x+y)+g(x+y)g(x-y)=f(x)f(y)+2g(x)+g ...
Aissi Youssef +2 more
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A Parametric Functional Equation Originating from Number Theory
Annales Mathematicae Silesianae, 2022 Let S be a semigroup and α, β ∈ ℝ. The purpose of this paper is to determine the general solution f : ℝ2 → S of the following parametric functional equation f(x1+x2+αy1y2,x1y2+x2y1+βy1y2)=f(x1,y1)f(x2,y2),f\left( {{x_1} + {x_2} + \alpha {y_1}{y_2},{x_1 ...
Mouzoun Aziz +2 more
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Sine Subtraction Laws on Semigroups
Annales Mathematicae Silesianae, 2023 We consider two variants of the sine subtraction law on a semi-group S. The main objective is to solve f(xy∗ ) = f(x)g(y) − g(x)f(y) for unknown functions f, g : S → ℂ, where x ↦ x* is an anti-homomorphic involution.
Ebanks Bruce
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Open Mathematics, 2020 Consider an ordered Banach space and f,gf,g two self-operators defined on the interior of its positive cone. In this article, we prove that the equation f(X)=g(X)f(X)=g(X) has a positive solution, whenever f is strictly α\alpha -concave g-monotone or ...
Kedim Imed +2 more
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Applications of the Sylvester operator in the space of slice semi-regular functions
Concrete Operators, 2020 In this paper we apply the results obtained in [3] to establish some outcomes of the study of the behaviour of a class of linear operators, which include the Sylvester ones, acting on slice semi-regular functions. We first present a detailed study of the
Amedeo Altavilla, de Fabritiis Chiara
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Un algoritmo tipo Newton globalizado para resolver la ecuación cuadrática matricial
Revista de la integracion, 2018 Resumen. En este artículo se presenta una globalización del algoritmo cuasiNewton local propuesto en [16] para resolver la ecuación cuadrática matricial.
Mauricio Macías +2 more
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Diagonal common quadratic Lyapunov functions for sets of positive LTI systems
, 2014 This paper focuses on the problems of a diagonal common quadratic Lyapunov function (DCQLF) existence for sets of stable positive linear time-invariant (LTI) systems.
Xiuyong Ding, L. Shu, Xiu Liu
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On Cauchy-type functional equations
International Journal of Mathematics and Mathematical Sciences, 2004 consider the functional equationsG f (xty)dµ(t) = n=1 gi(x)hi(y), x, y ∈ G, where the functions f , {gi}, {hi}: G → C to be determined are bounded and continuous functions on G.
E. Elhoucien, M. Akkouchi
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A result concerning two-sided centralizers on algebras with involution
, 2013 The purpose of this paper is to prove the following result. Let X be a complex Hilbert space, let L (X) be the algebra of all bounded linear operators on X and let A (X)⊂ L (X) be a standard operator algebra, which is closed under the adjoint operation ...
Nejc Širovnik, J. Vukman
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