共查询到20条相似文献,搜索用时 15 毫秒
1.
An approximate martingale estimating function with an eigenfunction is proposed for an estimation problem about an unknown drift parameter for a one-dimensional diffusion process with small perturbed parameter ε from discrete time observations at n regularly spaced time points k/n, k=0,1,…,n. We show asymptotic efficiency of an M-estimator derived from the approximate martingale estimating function as ε→0 and n→∞ simultaneously. 相似文献
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The subconstituents of the orthogonal graph O(2ν+δ,q), where ν?2 and δ∈{1,2}, over a finite field of odd characteristic are shown to be quasi-strongly regular. Furthermore, the first subconstituent is shown to be co-edge regular, and when ν?3 its automorphism group is determined. The second subconstituent is shown to be edge regular, and when ν?2 its automorphism group is determined. Their parameters and chromatic numbers are also determined. 相似文献
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Let K be a closed convex subset of a q-uniformly smooth separable Banach space, T:K→K a strictly pseudocontractive mapping, and f:K→K an L-Lispschitzian strongly pseudocontractive mapping. For any t∈(0,1), let xt be the unique fixed point of tf+(1-t)T. We prove that if T has a fixed point, then {xt} converges to a fixed point of T as t approaches to 0. 相似文献
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Let M be a closed subspace of a separable, infinite dimensional Hilbert space H with dim(H/M)=∞. We show that a bounded linear operator A:M→M has an invertible chaotic extension T:H→H if and only if A is bounded below. Motivated by our result, we further show that A:M→M has a chaotic Fredholm extension T:H→H if and only if A is left semi-Fredholm. 相似文献
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For a countable ultrahomogeneous graph G=〈G,ρ〉 let P(G) denote the collection of sets A⊂G such that 〈A,ρ∩[A]2〉≅G. The order types of maximal chains in the poset 〈P(G)∪{∅},⊂〉 are characterized as: 相似文献
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Let E be a real Banach space, C be a nonempty closed convex subset of E and T:C→C be a continuous generalized Φ-pseudocontractive mapping. It is proved that T has a unique fixed point in C. 相似文献
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A weak selection on an infinite set X is a function σ:[X]2→X such that σ({x,y})∈{x,y} for each {x,y}∈[X]2. A weak selection on a space is said to be continuous if it is a continuous function with respect to the Vietoris topology on [X]2 and the topology on X . We study some topological consequences from the existence of a continuous weak selection on the product X×Y for the following particular cases:
- (i)
- Both X and Y are spaces with one non-isolated point. 相似文献
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Let α:G×M→M be a differentiable action of a Lie group G on a connected differentiable manifold M. Assume that the local tube theorem holds at every x∈M. Then the following is proved: there is a maximal infinitesimal orbit type, called the principal, such that the union of the orbits belonging to this infinitesimal type is an open and dense set in M. 相似文献
10.
Let G denote a locally compact Hausdorff group and M(G) be the space of all bounded complex-valued regular Borel measures on G . In this paper, we define two strict topologies on M(G) and study various properties of these topologies such as metrizability, barrelledness and completeness. We also determine the dual space of M(G) and consider various continuity properties for the convolution product on M(G) under these topologies. 相似文献
11.
Mathias Beiglböck Walter SchachermayerBezirgen Veliyev 《Stochastic Processes and their Applications》2012
Every submartingale S of class D has a unique Doob–Meyer decomposition S=M+A, where M is a martingale and A is a predictable increasing process starting at 0. 相似文献
12.
Let M=(mij) be a nonnegative irreducible n×n matrix with diagonal entries 0. The largest eigenvalue of M is called the spectral radius of the matrix M , denoted by ρ(M). In this paper, we give two sharp upper bounds of the spectral radius of matrix M. As corollaries, we give two sharp upper bounds of the distance matrix of a graph. 相似文献
13.
Let F be an infinite field with characteristic not equal to two. For a graph G=(V,E) with V={1,…,n}, let S(G;F) be the set of all symmetric n×n matrices A=[ai,j] over F with ai,j≠0, i≠j if and only if ij∈E. We show that if G is the complement of a partial k -tree and m?k+2, then for all nonsingular symmetric m×m matrices K over F, there exists an m×n matrix U such that UTKU∈S(G;F). As a corollary we obtain that, if k+2?m?n and G is the complement of a partial k-tree, then for any two nonnegative integers p and q with p+q=m, there exists a matrix in S(G;R) with p positive and q negative eigenvalues. 相似文献
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We show that if T:X→X is a continuous linear operator on an F-space X≠{0}, then the set of frequently hypercyclic vectors of T is of first category in X, and this answers a question of A. Bonilla and K.-G. Grosse-Erdmann. We also show that if T:X→X is a bounded linear operator on a Banach space X≠{0} and if T is frequently hypercyclic (or, more generally, syndetically transitive), then the T∗-orbit of every non-zero element of X∗ is bounded away from 0, and in particular T∗ is not hypercyclic. 相似文献
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Let M be a 3-connected binary matroid and let n be an integer exceeding 2. Ding, Oporowski, Oxley, and Vertigan proved that there is an integer f(n) so that if |E(M)|>f(n), then M has a minor isomorphic to one of the rank-n wheel, the rank-n tipless binary spike, or the cycle or bond matroid of K3,n. This result was recently extended by Chun, Oxley, and Whittle to show that there is an integer g(n) so that if |E(M)|>g(n) and x∈E(M), then x is an element of a minor of M isomorphic to one of the rank-n wheel, the rank-n binary spike with a tip and a cotip, or the cycle or bond matroid of K1,1,1,n. In this paper, we prove that, for each i in {2,3}, there is an integer hi(n) so that if |E(M)|>hi(n) and Z is an i-element rank-2 subset of M, then M has a minor from the last list whose ground set contains Z. 相似文献
19.
Let f:X→Y be a morphism between normal complex varieties, where Y is Kawamata log terminal. Given any differential form σ, defined on the smooth locus of Y, we construct a “pull-back form” on X. The pull-back map obtained by this construction is ?Y-linear, uniquely determined by natural universal properties and exists even in cases where the image of f is entirely contained in the singular locus of Y. 相似文献
20.
In this paper, we consider the problem (Pε) : Δ2u=un+4/n-4+εu,u>0 in Ω,u=Δu=0 on ∂Ω, where Ω is a bounded and smooth domain in Rn,n>8 and ε>0. We analyze the asymptotic behavior of solutions of (Pε) which are minimizing for the Sobolev inequality as ε→0 and we prove existence of solutions to (Pε) which blow up and concentrate around a critical point of the Robin's function. Finally, we show that for ε small, (Pε) has at least as many solutions as the Ljusternik–Schnirelman category of Ω. 相似文献