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1.
A finite support product of clones of Jensen's minimal singleton forcing is used to define a model in which any non-empty analytically definable set of reals contains an analytically definable real (the full basis theorem), but there is no analytically definable wellordering of the reals. 相似文献
2.
Paul Bankston 《Archive for Mathematical Logic》2006,45(1):97-112
The Chang-Łoś-Suszko theorem of first-order model theory characterizes universal-existential classes of models as just those
elementary classes that are closed under unions of chains. This theorem can then be used to equate two model-theoretic closure
conditions for elementary classes; namely unions of chains and existential substructures. In the present paper we prove a
topological analogue and indicate some applications. 相似文献
3.
Necessary conditions for the Gâteaux differentiability of the distance function to a set are considered. A series of characterizing results is obtained. 相似文献
4.
设函数f(w)为凸区域D内的单叶解析函数,对于2≤n≤8和所有w∈D,本文得到估计式|f(n)(w)/f'(w)|的精确上界.这个结果推广了一些已知的结论. 相似文献
5.
This paper solves the problem of the duration of the total eclipseof a satellite of a body, provided that (a) the body is sphericalin shape and the mass distribution inside the body is sphericallysymmetrical; (b) the satellite is a very small object; (c) thesatellite's orbit around a body is circular and the satellitecan pass through the centre of its shadow; (d) a source of lightis the source of the conical body's shadow (umbra) and it doesnot change its apparent position in the sky; (e) there are noperturbations on the satellite's orbit. The solution presentedrepresents the general discussion of the problem based on utilizationof some parts of the theory of contraction mappings. 相似文献
6.
We extend the matrix version of Cochran's statistical theorem to outer inverses of a matrix. As applications, we investigate the Wishartness and independence of matrix quadratic forms for Kronecker product covariance structures. 相似文献
7.
8.
For an arbitrary bounded closed set E in the complex plane with complement Ω of finite connectivity, we study the degree of convergence of the lemniscates in Ω. 相似文献
9.
Bogdan Ka
mierczak Kazimierz Piechr 《Mathematical Methods in the Applied Sciences》2004,27(11):1317-1345
In this paper we study travelling wave solutions to a system of four non‐linear partial differential equations, which arise in a tissue interaction model for skin morphogenesis. Under the ‘small‐stress’ assumption we prove the existence and uniqueness (up to a translation) of solutions with the dermis and epidermis cell densities being positive, which are a perturbation of a uniform epidermal cell density. We discuss the problem of the minimal wave‐speed. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
10.
Mean value in invexity analysis 总被引:1,自引:0,他引:1
In this paper, a generalization of the mean value theorem is considered in the case of functions defined on an invex set with respect to η (which is not necessarily connected). 相似文献