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991.
For a subset ψ of PG(N, 2) a known result states that ψ has polynomial degree ≤ r, r≤ N, if and only if ψ intersects every r-flat of PG(N, 2) in an odd number of points. Certain refinements of this result are considered, and are then applied in the case when
ψ is the Grassmannian
, to show that for n <8 the polynomial degree of
is
. 相似文献
992.
Hans-Joachim Baues 《Compositio Mathematica》1998,110(1):50-64
For manifolds M,M of the form S2 e4 e6 we compute the homomorphisms H*M H*M between homology groups which are realizable by a map F: M M. 相似文献
993.
We consider the spaceL(D) consisting of Lipschitz continuous mappings fromD to the Euclideann-space
n
,D being an open bounded subset of
n
. LetF belong toL(D) and suppose that
solves the equationF(x) = 0. In case that the generalized Jacobian ofF at
is nonsingular (in the sense of Clarke, 1983), we show that forG nearF (with respect to a natural norm) the systemG(x) = 0 has a unique solution, sayx(G), in a neighborhood of
Moreover, the mapping which sendsG tox(G) is shown to be Lipschitz continuous. The latter result is connected with the sensitivity of strongly stable stationary points in the sense of Kojima (1980); here, the linear independence constraint qualification is assumed to be satisfied. 相似文献
994.
A. Milandri F. AsllanajG. Jeandel J.R. Roche 《Journal of Quantitative Spectroscopy & Radiative Transfer》2002,74(5):585-603
Coupled radiative and conductive heat transfer in a fibrous medium formed by silica fibres is investigated in this paper by not taking account of the axial symmetry for the distribution of fibres or the boundary conditions. Radiative properties of the medium are calculated by using the Mie theory. The model obtained depends only on optical parameters (indices of silica) and on morphological parameters (diameter and orientation of the fibres, density of the medium). Simulations make it possible to study the strongly anisotropic behaviour of the scattering of the radiation by a fibre and to study the influence of various parameters on the radiative properties of the medium. The results of the Mie theory make possible the simulation of the heat transfer coupled by radiation and conduction. To do this, we introduce a new numerical scheme able to simulate heat transfer in the lack of axial symmetry. With this model, we can show the effects of distribution of fibres and temperature on the thermal behaviour of the medium as well as showing the importance of the phenomenon of scattering in fibrous media. 相似文献
995.
在M enger PN空间中研究了一类非线性算子方程T x=μx p(μ≥1)的解,得到了几个新的定理.同时,改进和推广了若干个重要结论. 相似文献
996.
Menger PN空间中的固有值与固有元 总被引:4,自引:0,他引:4
本文提出了Menger PN空间中固有值和固有元的新概念,研究了M—PN空间中的固有值与固有元的若干问题,得到了几个重要的结论. 相似文献
997.
998.
In this paper, we consider a three-species ratio-dependent predator-prey model governed by difference equations with periodic coefficients. By using the method of coincidence degree, we discuss the existence of positive periodic solutions of this system, a set of easily verifiable sufficient conditions are derived. 相似文献
999.
Let cd(G) be the set of irreducible complex character degrees of a finite group G. The degree graph of G related to cd(G) was defined. It was proved many finite simple groups (but not all Mathieu groups) are uniquely determined by their orders and degree graphs. We hope to define a new graph related to cd(G) such that more simple groups can be uniquely determined by their orders and this newly defined graphs. Here a degree prime-power graph is defined and it is proved that all Mathieu groups can be determined uniquely by their orders and degree prime-power graphs. 相似文献
1000.
现有多方案决策中的指标权重计算方法可能产生评价结果中较优方案不突出的难题,进而提出了一种新的方法——基于较优方案最大区别度的组合权重赋值法.方法可根据方案间区别度最大的原则将主观赋权法和客观赋权法中所确定的指标权重进行集结,综合考量待评方案,并建立多方案决策结果最大化和决策结果间方差最大化非线性优化模型,采用理想点法对具体的多目标规划问题进行求解.方法的运用有利于扩大备选方案之间的差距,进而突出较优方案,最后通过实例说明了该方法的优越性. 相似文献