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Positive definiteness is not enough
Mathematical Geology, 1992Geostatisticians know that the mathematical functions chosen to represent spatial covariances and variograms must have the appropriate type of positive definiteness, but they may not realize that there are restrictions on the types of covariances and variograms that are compatible with particular distributions.
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On a criterion of positive definiteness
1997Let s(x) be a continuous function on (-a, a) such that (i) s(x) = s(-x) for -a 0, then there exists a neighborhood of 0 such that s(x) is positive definite in this neighborhood and admits more than one positive definite continuation from this neighborhood onto the whole real axis.
V. P. Potapov, Irina V. Mikhailova
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Monatshefte für Mathematik, 1975
In this paper we study the Fourier transform of unbounded measures on a locally compact groupG. After a short introductory section containing background material, especially results established byL. Argabright andJ. Gil De Lamadrid we turn to the main subjects of the paper: first we characterize
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In this paper we study the Fourier transform of unbounded measures on a locally compact groupG. After a short introductory section containing background material, especially results established byL. Argabright andJ. Gil De Lamadrid we turn to the main subjects of the paper: first we characterize
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Sibling Position and Definition of Self
The Journal of Social Psychology, 1971(1971). Sibling Position and Definition of Self. The Journal of Social Psychology: Vol. 84, No. 2, pp. 307-308.
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Quadratic Model Updating with Symmetry, Positive Definiteness, and No Spill-Over
SIAM Journal on Matrix Analysis and Applications, 2009Updating a system modeled as a real symmetric quadratic eigenvalue problem to match observed spectral information has been an important task for practitioners in different disciplines. It is often desirable in the process to match only the newly measured
D. Chu, M. Chu, Wen-Wei Lin
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An Eigenvalue Method for Testing Positive Definiteness of a Multivariate Form
IEEE Transactions on Automatic Control, 2008In this paper, we present an eigenvalue method for testing positive definiteness of a multivariate form. This problem plays an important role in the stability study of nonlinear autonomous systems via Lyapunov's direct method in automatic control.
Q. Ni, L. Qi, Fei Wang
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Positive definiteness in coupled strain gradient elasticity
Continuum Mechanics and Thermodynamics, 2020L. Nazarenko, R. Glüge, H. Altenbach
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Z-Eigenvalues-Based Sufficient Conditions for the Positive Definiteness of Fourth-Order Tensors
Bulletin of the Malaysian Mathematical Sciences Society, 2020Jun He, Yan-min Liu, Guangjun Xu
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A definition of positivity and negativity
2019In the last chapter we got a first glance at the positivist thesis. In its formulation, an operator was employed, symbolized by “+” in the upper right of the sentence it applies to. This operator might be read as “it is positively the case that”.
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A necessary and sufficient condition for the positive-definiteness of interval symmetric matrices
, 1986A necessary and sufficient condition for the positive-definiteness of interval symmetric matrices is obtained, and a useful application is shown.
Zhi-Cheng Shi, Weimin Gao
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