排序方式: 共有38条查询结果,搜索用时 15 毫秒
1.
Zinoviy Grinshpun 《Proceedings of the American Mathematical Society》2003,131(5):1591-1600
We prove the following theorem. Any isometric operator , that acts from the Hilbert space with nonnegative weight to the Hilbert space with nonnegative weight , allows for the integral representation
where the kernels and satisfy certain conditions that are necessary and sufficient for these kernels to generate the corresponding isometric operators.
where the kernels and satisfy certain conditions that are necessary and sufficient for these kernels to generate the corresponding isometric operators.
2.
3.
O. Chaban Z. Hotra J. Ilnytskyi A. Fechan V. Kotsun Z. Mykytyuk 《Molecular Crystals and Liquid Crystals》2015,611(1):160-170
Liquid crystalline materials can be used as an active media for the new generation of planar light guides. The main characteristics which governs light-guiding and switching abilities of such devices are the spatial distributions of the refraction indices (defined via the distribution of nematic director) for the liquid crystal confined within a light-guiding pore. We aim to obtain these distributions from the molecular dynamics simulation of the liquid crystalline cell with the homeotropic boundary conditions being applied. We discuss the reorientation kinetics of the homeotropic-planar transition and obtain the equilibrium director profile upon application of the planar reorienting field. 相似文献
4.
We study the problem of factorisation of non-negative Fredholm operators acting in the Hilbert space L2(0, 1) and its relation to the inverse spectral problem for Bessel operators. In particular, we derive an algorithm of reconstructing
the singular potential of the Bessel operator from its spectrum and the sequence of norming constants. 相似文献
5.
Fima C. Klebaner Zinoviy Landsman 《Methodology and Computing in Applied Probability》2009,11(3):339-357
We derive an option pricing formula on assets with returns distributed according to a log-symmetric distribution. Our approach
is consistent with the no-arbitrage option pricing theory: we propose the natural risk-neutral measure that keeps the distribution
of returns in the same log-symmetric family reflecting thus the specificity of the stock’s returns. Our approach also provides
insights into the Black–Scholes formula and shows that the symmetry is the key property: if distribution of returns X is log-symmetric then 1/X is also log-symmetric from the same family. The proposed options pricing formula can be seen as a generalization of the Black–Scholes
formula valid for lognormal returns. We treat an important case of log returns being a mixture of symmetric distributions
with the particular case of mixtures of normals and show that options on such assets are underpriced by the Black–Scholes
formula. For the log-mixture of normal distributions comparisons with the classical formula are given.
相似文献
6.
Let S be the multiplication operator by an independent variable x in L
2(0,1), and let V be an integral operator of Volterra type. In this note, we find sufficient conditions for the similarity of the operators T := S + V and S and discuss some generalizations to an abstract setting of the results obtained. 相似文献
7.
We study a multivariate extension of the univariate exponential dispersion Tweedie family of distributions. The class, referred to as the multivariate Tweedie family (MTwF), on the one hand includes multivariate Poisson, gamma, inverse Gaussian, stable and compound Poisson distributions and on the other hand introduces a high variety of new dependent probabilistic models unstudied so far. We investigate various properties of MTwF and discuss its possible applications to financial risk management. 相似文献
8.
Zinoviy Landsman 《Insurance: Mathematics and Economics》2010,46(3):547-553
In the present paper we propose the Tail Mean-Variance (TMV) approach, based on Tail Condition Expectation (TCE) (or Expected Short Fall) and the recently introduced Tail Variance (TV) as a measure for the optimal portfolio selection. We show that, when the underlying distribution is multivariate normal, the TMV model reduces to a more complicated functional than the quadratic and represents a combination of linear, square root of quadratic and quadratic functionals. We show, however, that under general linear constraints, the solution of the optimization problem still exists and in the case where short selling is possible we provide an analytical closed form solution, which looks more “robust” than the classical MV solution. The results are extended to more general multivariate elliptical distributions of risks. 相似文献
9.
A. K. Prykarpatsky D. L. Blackmore Ya. V. Mykytyuk 《Journal of Mathematical Sciences》2001,104(5):1411-1421
This article is a continuation of [J. Math. Sci., 99, No.5, 1541–1547 (2000)] devoted to the validity of the Lax formula (cited in the article of Crandall, Ishii, and Lions [Bull. AMS, 27, No.1, 1–67 (2000)])
for a solution to the Hamilton–Jacobi nonlinear partial differential equation
where the Cauchy data
are now a function semicontinuous from below,
is the usual norm in
,
, and
is a positive evolution parameter. We proved that the Lax formula solves the Cauchy problem (2) at all points
,
fixed save for an exceptional set of points R of the F
type, having zero Lebesgue measure. In addition, we formulate a similar Lax-type formula without proof for a solution to a new nonlinear equation of the Hamilton–Jacobi-type:
where
is a diagonal positive-definite matrix, mentioned in Part I and having interesting applications in modern mathematical physics. 相似文献
10.
Zinoviy Landsman 《Journal of multivariate analysis》2008,99(5):912-927
For the family of multivariate normal distribution functions, Stein's Lemma presents a useful tool for calculating covariances between functions of the component random variables. Motivated by applications to corporate finance, we prove a generalization of Stein's Lemma to the family of elliptical distributions. 相似文献