Results 11 to 20 of about 9,956,543 (298)
Strictly Positive Definite Functions [PDF]
Journal of Approximation Theory, 1996 A complex-valued continuous function defined on \(\mathbb{R}\) is said to be strictly positive definite on \(\mathbb{R}\) if the \(n\) by \(n\) matrix \((f(x_i- x_j))\) is positive definite for all choices of pairwise distinct points \(x_1,x_2,\dots,x_n\in\mathbb{R}\), and all \(n\geq 1\).
Chang, Kuei-Fang
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On unbounded positive definite functions [PDF]
, 2018 It is well known that positive definite functions are bounded, taking their maximum absolute value at 0. Nevertheless, there are unbounded functions, arising e.g. in potential theory or the study of (continuous) extremal measures, which still exhibit the
Phillips, Tomos, Schmidt, Karl Michael
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Extrapolated positive definite and positive semi-definite splitting methods for solving non-Hermitian positive definite linear systems [PDF]
, 2022 summary:Recently, Na Huang and Changfeng Ma in (2016) proposed two kinds of typical practical choices of the PPS method. In this paper, we extrapolate two versions of the PPS iterative method, and we introduce the extrapolated Hermitian and skew ...
Shokrpour, Raheleh, Ebadi, Ghodrat
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Continuations of Hermitian indefinite functions and corresponding canonical systems : an example [PDF]
, 2004 M. G. Krein established a close connection between the continuation problem of positive definite functions from a finite interval to the real axis and the inverse spectral problem for differential operators.
Sasvári, Zoltán +2 more
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Convolution roots and differentiability of isotropic positive definite functions on spheres [PDF]
, 2014 We prove that any isotropic positive definite function on the sphere can be written as the spherical self-convolution of an isotropic real-valued function.
Ziegel, Johanna F.
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On a uniqueness theorem for characteristic functions
Nonlinear Analysis, 2017 Suppose that f is the characteristic function of a probability measure on the real line R. We deal with the following open problem posed by N.G. Ushakov: Is it true that f is never determined by its imaginary part Im f?
Saulius Norvidas
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Unitary representability of free abelian topological groups
Applied General Topology, 2008 For every Tikhonov space X the free abelian topological group A(X) and the free locally convex vector space L(X) admit a topologically faithful unitary representation. For compact spaces X this is due to Jorge Galindo.
Vladimir V. Uspenskij
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Class- Function Bounds for Positive Definite Functions on Compact Sets
, 2020 This technical note focuses on positive definite functions defined on compact sets which contain the origin in their interior. It provides a class-K$$\mathcal{K}$$ function bounding inequality for the given positive definite function which is satisfied ...
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Functional Calculus and Positive-Definite Functions [PDF]
Transactions of the American Mathematical Society, 1977 For a LCA group G with dual group Ĝ , let D ( G
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SMARANDACHE SPECIAL DEFINITE ALGEBRAIC STRUCTURES [PDF]
, 2009 Introducing the notion of Smarandache special definite algebraic structures, also called equivalently as Smarandache definite special algebraic structures.
Vasantha, Kandasamy
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