scholarly journals Sharp multidimensional numerical integration for strongly convex functions on convex polytopes

Filomat ◽  
2020 ◽  
Vol 34 (2) ◽  
pp. 601-607
Author(s):  
Osama Alabdali ◽  
Allal Guessab
Keyword(s):  
Numerical Integration ◽  
Convex Polytopes ◽  
Sufficient Conditions ◽  
Approximation Error ◽  
Quadratic Function ◽  
Characterization Theorem ◽  
Strongly Convex ◽  
Cubature Formulas ◽  
Voronoi Tesselations ◽  
Necessary And Sufficient

This paper introduces and studies a new class of multidimensional numerical integration, which we call ?strongly positive definite cubature formulas?. We establish, among others, a characterization theorem providing necessary and sufficient conditions for the approximation error (based on such cubature formulas) to be bounded by the approximation error of the quadratic function. This result is derived as a consequence of two characterization results, which are of independent interest, for linear functionals obtained in a more general seeting. Thus, this paper extends some result previously reported in [2, 3] when convexity in the classical sense is only assumed. We also show that the centroidal Voronoi Tesselations provide an efficient way for constructing a class of optimal of cubature formulas. Numerical results for the two-dimensional test functions are given to illustrate the efficiency of our resulting cubature formulas.

Some results on normal GCR-lightlike submanifolds of indefinite nearly Kaehler manifolds

2019 ◽  
Vol 16 (03) ◽  
pp. 1950037
Author(s):  
Megha ◽  
Sangeet Kumar
Keyword(s):  
Sufficient Conditions ◽  
Characterization Theorem ◽  
Kaehler Manifold ◽  
Kaehler Manifolds ◽  
Holomorphic Bisectional Curvature ◽  
Necessary And Sufficient ◽  
Nearly Kaehler Manifold ◽  
Lightlike Submanifolds ◽  
Lightlike Submanifold ◽  
Normal Formula

The purpose of this paper is to study normal [Formula: see text]-lightlike submanifolds of indefinite nearly Kaehler manifolds. We find some necessary and sufficient conditions for an isometrically immersed [Formula: see text]-lightlike submanifold of an indefinite nearly Kaehler manifold to be a normal [Formula: see text]-lightlike submanifold. Further, we derive a characterization theorem for holomorphic bisectional curvature of a normal [Formula: see text]-lightlike submanifold of an indefinite nearly Kaehler manifold.

scholarly journals Note on Cubature Formulae and Designs Obtained from Group Orbits

2012 ◽  
Vol 64 (6) ◽  
pp. 1359-1377 ◽  
Author(s):  
Hiroshi Nozaki ◽  
Masanori Sawa
Keyword(s):  
Cubature Formula ◽  
Sufficient Conditions ◽  
Reflection Group ◽  
Alternative Proof ◽  
Invariant Polynomials ◽  
Cubature Formulas ◽  
Finite Reflection Group ◽  
Necessary And Sufficient ◽  
Cubature Formulae ◽  
Invariant Cubature Formulas

Abstract In 1960, Sobolev proved that for a finite reflection group G, a G-invariant cubature formula is of degree t if and only if it is exact for all G-invariant polynomials of degree at most t . In this paper, we make some observations on invariant cubature formulas and Euclidean designs in connection with the Sobolev theorem. First, we give an alternative proof of theorems by Xu (1998) on necessary and sufficient conditions for the existence of cubature formulas with some strong symmetry. The new proof is shorter and simpler compared to the original one by Xu, and, moreover, gives a general interpretation of the analytically-written conditions of Xu's theorems. Second, we extend a theorem by Neumaier and Seidel (1988) on Euclidean designs to invariant Euclidean designs, and thereby classify tight Euclidean designs obtained from unions of the orbits of the corner vectors. This result generalizes a theorem of Bajnok (2007), which classifies tight Euclidean designs invariant under the Weyl group of type B, to other finite reflection groups.

scholarly journals Jensen-type geometric shapes

2020 ◽  
Vol 19 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Paweł Pasteczka
Keyword(s):  
Convex Function ◽  
Convex Polytopes ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Centre Of Mass ◽  
Geometric Shapes ◽  
Necessary And Sufficient

AbstractWe present both necessary and sufficient conditions for a convex closed shape such that for every convex function the average integral over the shape does not exceed the average integral over its boundary.It is proved that this inequality holds for n-dimensional parallelotopes, n-dimensional balls, and convex polytopes having the inscribed sphere (tangent to all its facets) with the centre in the centre of mass of its boundary.

scholarly journals An Appropriate Way to Switch from the Individual Risk Model to the Collective One

1993 ◽  
Vol 23 (1) ◽  
pp. 23-54 ◽  
Author(s):  
S. Kuon ◽  
M. Radtke ◽  
A. Reich
Keyword(s):  
Risk Model ◽  
Sufficient Conditions ◽  
Approximation Error ◽  
Individual Risk ◽  
Risk Models ◽  
Approximation Quality ◽  
Collective Risk Model ◽  
Collective Risk ◽  
The Individual ◽  
Necessary And Sufficient

AbstractFor some time now, the convenient and fast calculability of collective risk models using the Panjer-algorithm has been a well-known fact, and indeed practitioners almost always make use of collective risk models in their daily numerical computations. In doing so, a standard link has been preferred for relating such calculations to the underlying heterogeneous risk portfolio and to the approximation of the aggregate claims distribution function in the individual risk model. In this procedure until now, the approximation quality of the collective risk model upon which such calculations are based is unknown.It is proved that the approximation error which arises does not converge to zero if the risk portfolio in question continues to grow. Therefore, necessary and sufficient conditions are derived in order to obtain well-adjusted collective risk models which supply convergent approximations. Moreover, it is shown how in practical situations the previous natural link between the individual and the collective risk model can easily be modified to improve its calculation accuracy. A numerical example elucidates this.

scholarly journals On warped product semi-slant submanifolds of nearly Trans-Sasakian manifolds

Filomat ◽  
2018 ◽  
Vol 32 (17) ◽  
pp. 5845-5856
Author(s):  
Akram Ali ◽  
Ali Alkhaldi ◽  
Rifaqat Ali
Keyword(s):  
Warped Product ◽  
Sufficient Conditions ◽  
Characterization Theorem ◽  
Sasakian Manifold ◽  
Necessary And Sufficient Conditions ◽  
Sasakian Manifolds ◽  
Slant Submanifold ◽  
Slant Submanifolds ◽  
Necessary And Sufficient

In this paper, we study warped product semi-slant submanifold of type M = NT xf N? with slant fiber, isometrically immersed in a nearly Trans-Sasakian manifold by finding necessary and sufficient conditions in terms of Weingarten map. A characterization theorem is proved as main result.

Study of lump and lump-kink solitons of a coupled reduced Hirota bilinear equation

2020 ◽  
Vol 34 (22) ◽  
pp. 2050224
Author(s):  
Shun Wang ◽  
Chuanzhong Li ◽  
Zhenli Wang
Keyword(s):  
Sufficient Conditions ◽  
Quadratic Function ◽  
Quadratic Functions ◽  
Bulk Solution ◽  
Lump Solutions ◽  
Weakly Coupled ◽  
Hirota Bilinear Equation ◽  
Necessary And Sufficient ◽  
Hirota Bilinear ◽  
Bilinear Equation

By symbolic computation and searching for the solutions of the positive quadratic functions of the related bilinear equations, two kinds of lump solutions of the (3[Formula: see text]+[Formula: see text]1)-dimensional weakly coupled Hirota bilinear equation are derived, and the practicability of this method is verified. Then we add an exponential function to the original positive quadratic function, and obtain a new solution of the Hirota bilinear equation. The interaction between the lump solutions and lump-kink solutions is included in the new solution. On this basis, we give the possibility of adding multiple exponential functions. Finally, we give the coupled reduced Hirota bilinear equation lump-kink solitons by combining the above two methods. In order to ensure the analyticity and reasonable localization of the block, two sets of necessary and sufficient conditions are given for the parameters involved in the solution. The local characteristics and energy distribution of bulk solution are analyzed and explained.

scholarly journals Approximation of entire functions over Carathéodory domains

1982 ◽  
Vol 25 (2) ◽  
pp. 221-229 ◽  
Author(s):  
G.P. Kapoor ◽  
A. Nautiyal
Keyword(s):  
Entire Function ◽  
Analytic Continuation ◽  
Finite Type ◽  
Finite Order ◽  
Jordan Curve ◽  
Entire Functions ◽  
Sufficient Conditions ◽  
Approximation Error ◽  
Image Position ◽  
Necessary And Sufficient

Let D be a domain bounded by a Jordan curve. For 1 ≤ p ≤ ∞, let Lp(D) be the class of all functions f holomorphic in D such that where A is the area of D. For f ∈Lp(D), setπn consists of all polynomials of degree at most n. Recently, Andre Giroux (J. Approx. Theory 28 (1980), 45–53) has obtained necessary and sufficient conditions, in terms of the rate of decrease of the approximation error , such that has an analytic continuation as an entire function having finite order and finite type. In the present paper we have considered the approximation error (*) on a Carathéodory domain and have extended the results of Giroux for the case 1 ≤ p < 2.

scholarly journals Radical transversal SCR-lightlike submanifolds of indefinite Sasakian manifolds

Filomat ◽  
2021 ◽  
Vol 35 (8) ◽  
pp. 2585-2594
Author(s):  
S.S. Shukla ◽  
Akhilesh Yadav
Keyword(s):  
Sufficient Conditions ◽  
Characterization Theorem ◽  
Sasakian Manifold ◽  
Necessary And Sufficient Conditions ◽  
Sasakian Manifolds ◽  
Totally Geodesic ◽  
Integrability Conditions ◽  
Cauchy Riemann ◽  
Necessary And Sufficient ◽  
Lightlike Submanifolds

In this paper, we introduce the notion of radical transversal screen Cauchy-Riemann (SCR)- lightlike submanifolds of indefinite Sasakian manifolds giving characterization theorem with some nontrivial examples of such submanifolds. Integrability conditions of distributions D1, D2, D and D? on radical transversal SCR-lightlike submanifolds of an indefinite Sasakian manifold have been obtained. Further, we obtain necessary and sufficient conditions for foliations determined by above distributions to be totally geodesic.

On complex Berwald metrics which are not conformal changes of complex Minkowski metrics

2018 ◽  
Vol 18 (3) ◽  
pp. 373-384 ◽  
Author(s):  
Hongchuan Xia ◽  
Chunping Zhong
Keyword(s):  
Sufficient Conditions ◽  
Finsler Metrics ◽  
Hermitian Metrics ◽  
Strongly Convex ◽  
Projectively Flat ◽  
Convex Case ◽  
Minkowski Metrics ◽  
Complex Finsler Metrics ◽  
Necessary And Sufficient

AbstractWe investigate a class of complex Finsler metrics on a domain D ⊂ ℂn. Necessary and sufficient conditions for these metrics to be strongly pseudoconvex complex Finsler metrics, or complex Berwald metrics, are given. The complex Berwald metrics constructed in this paper are neither trivial Hermitian metrics nor conformal changes of complex Minkowski metrics. We give a characterization of complex Berwald metrics which are of isotropic holomorphic curvatures, and also give characterizations of complex Finsler metrics of this class to be Kähler Finsler or weakly Kähler Finsler metrics. Moreover, in the strongly convex case, we give characterizations of complex Finsler metrics of this class to be projectively flat Finsler metrics or dually flat Finsler metrics.

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