共查询到20条相似文献,搜索用时 593 毫秒
1.
The extremal coefficients are the natural dependence measures for multivariate extreme value distributions. For an m-variate distribution 2m distinct extremal coefficients of different orders exist; they are closely linked and therefore a complete set of 2m coefficients cannot take any arbitrary values. We give a full characterization of all the sets of extremal coefficients. To this end, we introduce a simple class of extreme value distributions that allows for a 1-1 mapping to the complete sets of extremal coefficients. We construct bounds that higher order extremal coefficients need to satisfy to be consistent with lower order extremal coefficients. These bounds are useful as lower order extremal coefficients are the most easily inferred from data. 相似文献
2.
冯小高 《纯粹数学与应用数学》2016,32(2):119-126
分别借助解析函数与调和函数两类函数的Dirichlet积分,利用相关文献给定边界值的拟共形映射极值伸缩商的估计方法,通过有限偏差函数和拟共形映射的关系估计了具有给定边界值的有限偏差函数的极值伸缩商.得到了解析函数的Dirichlet积分在有限偏差函数下具有拟不变性,同时给出有限偏差函数极值伸缩商的下界估计. 相似文献
3.
R. M. Garipov 《Journal of Applied and Industrial Mathematics》2011,5(3):331-342
We look for best mean-quasiconformal mappings as extremals of the functional equal to the integral of the square of the functional
of the conformality distortion multiplied by a special weight. The mapping inverse to an extremal is an extremal of the same
functional. We obtain necessary and sufficient conditions for the Petrovskii ellipticity of the system of Euler equations
for an extremal. We prove the local unique solvability of boundary values problems for this system in the 2-dimensional case.
In the general case we prove the unique solvability of boundary value problems for the system linearized at the identity mapping. 相似文献
4.
We investigate properties of the sequences of extremal values that could be achieved by the eigenvalues of the Laplacian on Euclidean domains of unit volume, under Dirichlet and Neumann boundary conditions, respectively. In a second part, we study sequences of extremal eigenvalues of the Laplace–Beltrami operator on closed surfaces of unit area. 相似文献
5.
We study extremal graphs for the extremal values of the second largest Q-eigenvalue of a connected graph. We first characterize all simple connected graphs with second largest signless Laplacian eigenvalue at most 3. The second part of the present paper is devoted to the study of the graphs that maximize the second largest Q-eigenvalue. We construct families of such graphs and prove that some of theses families are minimal for the fact that they maximize the second largest signless Laplacian eigenvalue. 相似文献
6.
拟共形映射与调和函数 总被引:1,自引:0,他引:1
本文利用调和函数的Dirichlet积分来估计具有给定边界值的拟共形映射的极值伸缩商,回答D.Partyka关于拟对称函数谱值和特征值的一个问题。 相似文献
7.
We analyse the structure of imprecise Markov chains and study their convergence by means of accessibility relations. We first identify the sets of states, so-called minimal permanent classes, that are the minimal sets capable of containing and preserving the whole probability mass of the chain. These classes generalise the essential classes known from the classical theory. We then define a class of extremal imprecise invariant distributions and show that they are uniquely determined by the values of the upper probability on minimal permanent classes. Moreover, we give conditions for unique convergence to these extremal invariant distributions. 相似文献
8.
Analysis Mathematica - In this paper, we investigate general Lp-mixed brightness integrals which were defined by Yan and Wang. We give their extremal values and establish Brunn-Minkowski type... 相似文献
9.
We calculate basic values of the double sine function. The algebraicity for some special values is proved. Its behavior in the fundamental domain is also studied. Especially we show that it has just two extremes: one relative maximum and one relative minimum. Asymptotic formulas for these extremal values are proved. 相似文献
10.
The Extremal Types Theorem identifies three distinct types of extremal behaviour. Two different strategies for statistical
inference for extreme values have been developed to exploit this asymptotic representation. One strategy uses a model for
which the three types are combined into a unified parametric family with the shape parameter of the family determining the
type: positive (Fréchet), zero (Gumbel), and negative (negative Weibull). This form of approach never selects the Gumbel type
as that type is reduced to a single point in a continuous parameter space. The other strategy first selects the extremal type,
based on hypothesis tests, and then estimates the best fitting model within the selected type. Such approaches ignore the
uncertainty of the choice of extremal type on the subsequent inference. We overcome these deficiencies by applying the Bayesian
inferential framework to an extended model which explicitly allocates a non-zero probability to the Gumbel type. Application
of our procedure suggests that the effect of incorporating the knowledge of the Extremal Types Theorem into the inference
for extreme values is to reduce uncertainty, with the degree of reduction depending on the shape parameter of the true extremal
distribution and the prior weight given to the Gumbel type. 相似文献
11.
We determine the maximum values of the reverse Wiener indices of the unicyclic graphs with given cycle length, number of pendent
vertices and maximum degree, respectively, and characterize the extremal graphs. We also determine the unicyclic graphs of
given cycle length and diameter with minimum Wiener index.
相似文献
12.
In this paper, binary extremal singly even self-dual codes of length 40 and extremal odd unimodular lattices in dimension 40 are studied. We give a classification of extremal singly even self-dual codes of length 40. We also give a classification of extremal odd unimodular lattices in dimension 40 with shadows having 80 vectors of norm 2 through their relationships with extremal doubly even self-dual codes of length 40. 相似文献
13.
T. I. Fedoryaeva 《Journal of Applied and Industrial Mathematics》2013,7(2):153-165
We study majorants (minorants) for the classes of n-vertex diameter d graphs, that is, the extremal graphs on which the sharp upper (lower) bounds are attained for the number of distinct radius i balls for every i ≥ 0. We explicitly describe the minorants for all values of n and d, determine when the class of n-vertex diameter d graphs contains majorants, and describe these extremal graphs. 相似文献
14.
V. Maume-Deschamps D. Rullière A. Usseglio-Carleve 《Methodology and Computing in Applied Probability》2018,20(2):643-671
In this work, we consider an elliptical random field. We propose some spatial expectile predictions at one site given observations of the field at some other locations. To this aim, we first give exact expressions for conditional expectiles, and discuss problems that occur for computing these values. A first affine expectile regression predictor is detailed, an explicit iterative algorithm is obtained, and its distribution is given. Direct simple expressions are derived for some particular elliptical random fields. The performance of this expectile regression is shown to be very poor for extremal expectile levels, so that a second predictor is proposed. We prove that this new extremal prediction is asymptotically equivalent to the true conditional expectile. We also provide some numerical illustrations, and conclude that Expectile Regression may perform poorly when one leaves the Gaussian random field setting. 相似文献
15.
ON EXTREMALITY AND UNIQUE EXTREMALITY OF TEICHMULLER MAPPINGS 总被引:2,自引:1,他引:1
ONEXTREMALITYANDUNIQUEEXTREMALITYOFTEICHMULLERMAPPINGS¥LAIWANCAI;WUZHEMINAbstract:ConsidertheTeichmullermappingfassociatedwit... 相似文献
16.
17.
Gary G. Gundersen 《Results in Mathematics》1989,16(1-2):54-76
We use the spread relation to prove estimates that contain the Nevanlinna deficiencies of values of meromorphic solutions of certain differential equations of the form (1.1) below. We construct examples which show that all of our estimates are sharp, and in most of these constructions we use functions which are extremal for the spread relation. Several other examples are also given to illustrate our results. 相似文献
18.
We study the existence of positive radially symmetric solutions to a class of nonlinear elliptic problems involving extremal operators and nonlinearity of exponential or polynomial type. According to the values of a parameter, we describe situations where the equation has one, finitely many, infinitely many or no solutions, by using the geometry structure of phase plane. 相似文献
19.
V. S. Klimov 《Mathematical Notes》2007,81(1-2):61-71
We study homology characteristics of critical values and extremals of Lipschitz functionals defined on bounded closed convex subsets of a reflexive space that are invariant under deformations. Sufficient conditions for the existence of a bifurcation point of a multivalued potential operator (the switch principle for the typical number of an extremal) are established. 相似文献
20.
We examine combinatorial properties of extremal plane stochastic matrices of dimension three. Methods are given for the construction of such extremal matrices of any order. We obtain a lower bound for the number of connected extremal matrices of order n and conclude with some open problems. 相似文献