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1.
F. Farid 《Linear and Multilinear Algebra》2002,50(3):223-239
An upper bound for the number of components of the numerical range of matrix polynomials is established. We also establish a necessary condition and a sufficient condition for the connectedness of the numerical range of a quadratic selfadjoint matrix polynomial. The boundary of the numerical range of linear matrix polynomials is also considered. 相似文献
2.
Jean Saint Raymond 《Rendiconti del Circolo Matematico di Palermo》1995,44(1):162-168
Let (T, ℐ, μ) be a σ-finite atomless measure space,p∈[1,∞),E a real Banach space andf a measurable function:E xT→ℝ. We denote byF the functionalF:
and byDom(F) its domain, it is the set {uεL
p(T,E):ū(t)=f(u),t)εL
1(T)}, and we prove that the sublevelsS(λ)={u:F(u)≤λ} are all connected in the subspaceDom(F) of the Banach spaceL
p(T, E). 相似文献
3.
We prove a connectedness result for products of weighted projective spaces. 相似文献
4.
While connected arithmetic discrete lines are entirely characterized, only partial results exist for the more general case of arithmetic discrete hyperplanes. In the present paper, we focus on the three-dimensional case, that is on arithmetic discrete planes. Thanks to arithmetic reductions on a vector , we provide algorithms either to determine whether a given arithmetic discrete plane with as normal vector is connected, or to compute the minimal thickness for which an arithmetic discrete plane with normal vector is connected. 相似文献
5.
6.
Amin Coja-Oghlan 《Discrete Mathematics》2009,309(13):4527-4544
We study the following min-min random graph process G=(G0,G1,…): the initial state G0 is an empty graph on n vertices (n even). Further, GM+1 is obtained from GM by choosing a pair {v,w} of distinct vertices of minimum degree uniformly at random among all such pairs in GM and adding the edge {v,w}. The process may produce multiple edges. We show that GM is asymptotically almost surely disconnected if M≤n, and that for M=(1+t)n, constant, the probability that GM is connected increases from 0 to 1. Furthermore, we investigate the number X of vertices outside the giant component of GM for M=(1+t)n. For constant we derive the precise limiting distribution of X. In addition, for n−1ln4n≤t=o(1) we show that tX converges to a gamma distribution. 相似文献
7.
Every finite disconnected set P is determined (up to automorphism) by the family {P − {a}:a ∈ Max
P
}. 相似文献
8.
本文研究局部凸的拓扑向量空间中锥拟凸多目标规划锥有效解集的连通性问题.证明了定义在紧凸集上目标映射为一对一的锥拟凸多目标规划的锥有效解集是连通的.在证明中,广义鞍点定理起着关键的作用. 相似文献
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10.
In this paper we study families of degree 2 parabolic-like mappings (fλ)λ∈Λ (as defined in [4]). We prove that the hybrid conjugacies between a nice analytic family of degree 2 parabolic-like mappings and members of the family Per1(1) induce a continuous map χ:Λ→C, which under suitable conditions restricts to a ramified covering from the connectedness locus of (fλ)λ∈Λ to the connectedness locus M1?{1} of Per1(1). As an application, we prove that the connectedness locus of the family Ca(z)=z+az2+z3, a∈C presents baby M1. 相似文献