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设MC=[A C 0 B]是从Hilbert空间H⊕K到H⊕K中的2×2上三角算子矩阵.该文主要研究MC的Drazin可逆性和MC的Drazin谱.此外,对给定算子A∈B(H)和B∈B(K),将给出在一定条件下所有上三角算子矩阵Mc的Drazin谱的交∩C∈B(K,K)σD(MC)的具体表达式. 相似文献
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设MG=[ O B^A C]是从Hilbert空间H+K到H+K中的2×2上三角算子矩阵.该文主要研究MC的Drazin可逆性和Mc的Drazin谱.此外,对给定算子A∈B(H)和B∈B(K),将给出在一定条件下所有上三角算子矩阵Mc的Drazin谱的交∩C∈B(K,H)σD(Mc)的具体表达式。 相似文献
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令{H}和{K}均为无限复可分的Hilbert空间. 定义MX=(A&C\\X&B\)为作用在{H}}\oplus{K}上的2x2算子矩阵, 其中X为从{H}到{K}上未知的有界线性算子.在本文中, 基于R(C)的闭性对某个(或任意的)X\in{B}}({H,K}}), 使得R(M_{X})为闭集的充要条件做了等价刻画.另外, 研究了算子矩阵M_{X的半Fredholm性与广义Weyl性并给出了一些相应的结论. 相似文献
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给定m×n阶矩阵A,我们给出了它的加边矩阵M=[A B C O] (1)为非奇的充分必要条件。其中O为r1×r2阶零矩阵。把M的逆矩阵记为分块形式M-1=[A1 B2 C3 O4]其中C1为n×m、C2为n×r1、C3为r2×m、C4为r2×r1阶矩阵。在一定条件下,我们证明了其中的C1为A的广义逆矩阵A+。 相似文献
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2×2阶上三角算子矩阵的谱扰动 总被引:2,自引:1,他引:1
研究了Hilbert空间H⊕K上的2×2阶上三角算子矩阵MC=(A O C B)当A,B给定,C为任意有界线性算子时,对MC的点谱、剩余谱、连续谱的扰动分别给出了描述. 相似文献
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A∈B(H)称为是一个Drazin可逆的算子,若A有有限的升标和降标.用σ_D(A)={λ∈C:A-λI不是Drazin可逆的)表示Drazin谱集.本文证明了对于Hilbert空间上的一个2×2上三角算子矩阵M_C=■,从σ_D(A)∪σ_D(G)到σ_D(M_C)的道路需要从前面子集中移动σ_D(A)∩σ_D(B)中一定的开子集,即有等式:σ_D(A)∪σ_D(B)=σ_D(M_C)∪G,其中G为σ_D(M_C)中一定空洞的并,并且为σ_D(A)∪σ_D(B)的子集.2×2算子矩阵不一定满足Weyl定理,利用Drazin谱,我们研究了2×2上三角算子矩阵的Weyl定理,Browder定理,a-Weyl定理和a-Browder定理. 相似文献
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一类缺项算子矩阵的四类点谱的扰动 总被引:1,自引:0,他引:1
有界线性算子的点谱可进一步细分为4类,分别为$\sigma_{p1}$, $\sigma_{p2}$, $\sigma_{p3}$ 和$\sigma_{p4}$.设 $H, K$为无穷维可分的Hilbert空间,用$M_C$表示$2\times 2$上三角算子矩阵$\left(\begin{array}{cc} A & C \\ 0 & B \\ \end{array} \right)$,对于给定的 $A\in B(H),~B\in B(K)$,描述了集合$\bigcap\limits_{C\in B(K,H)}\sigma_{p1}(M_C)$, $\bigcap\limits_{C\in B(K,H)}\sigma_{p2}(M_C)$, $\bigcap\limits_{C\in B(K,H)}\sigma_{p3}(M_C)$和$\bigcap\limits_{C\in B(K,H)}\sigma_{p4}(M_C)$. 相似文献
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设F2为两个元素组成的有限域, F2n 为F2上的n维向量空间. 对于集合A, B ⊆ F2n , 它们的和集定义为所有两两互异的和a+b所组成的集合, 其中a∈A, b∈B. Green 和Tao 证明了: 设K > 1,如果A, B ? F2n 且|A + B|≤K|A|1/2|B|1/2, 则存在一个子空间H?F2n 满足
|H|>>exp(-O(√KlogK))|A|
以及x,y∈F2n, 使得
|A∩(x+H)|1/2|B∩(y+H)|1/2≥1/2K|H|.
本文我们将使用Green 和Tao 的方法并作一些修改, 证明如果|H|>>exp(-O(√K))|A|,
则以上的结论仍然成立. 相似文献
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In this paper, we study the perturbation of spectra for 2 × 2 operator matrices such as M X = ( 0 B A X ) and M Z = ( Z B A C ) on the Hilbert space H ?? K and the sets $\bigcap\limits_{X \in \mathcal{B}(K,H)} {P_\sigma (M_X )} ,\bigcap\limits_{X \in \mathcal{B}(K,H)} {R_\sigma (M_X )} $ and $\bigcap\limits_{Z \in \mathcal{B}(H,K)} {\sigma (M_Z )} ,\bigcap\limits_{Z \in \mathcal{B}(H,K)} {P_\sigma (M_Z )} ,\bigcap\limits_{Z \in \mathcal{B}(H,K)} {R_\sigma (M_Z )} ,\bigcap\limits_{Z \in \mathcal{B}(H,K)} {C_\sigma (M_Z )} $ , where R(C) is a closed subspace, are characterized 相似文献
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设μ是R~d上的非负Radon测度,且满足增长性条件:存在一正常数C_0,使得对任意的x∈R~d和r0,有μ(B(x,r))≤C_0r~n,其中0n≤d.该文研究了相关于非双倍测度μ的Marcinkiewicz积分与RBMO函数生成的交换子,得到了这类交换子的加A_p~p(μ)权的弱型估计. 相似文献
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In the first part of the paper we introduce the theory of bundles with negatively curved fibers. For a space X there is a forgetful map F X between bundle theories over X, which assigns to a bundle with negatively curved fibers over X its subjacent smooth bundle. Our main result states that, for certain k-spheres ${\mathbb{S}^k}In the first part of the paper we introduce the theory of bundles with negatively curved fibers. For a space X there is a forgetful map F
X
between bundle theories over X, which assigns to a bundle with negatively curved fibers over X its subjacent smooth bundle. Our main result states that, for certain k-spheres
\mathbbSk{\mathbb{S}^k}, the forgetful map
F\mathbbSk{F_{\mathbb{S}^k}} is not one-to-one. This result follows from Theorem A, which proves that the quotient map MET sec < 0 (M)?T sec < 0 (M){\mathcal{MET}^{\,\,sec <0 }(M)\rightarrow\mathcal{T}^{\,\,sec <0 }(M)} is not trivial at some homotopy levels, provided the hyperbolic manifold M satisfies certain conditions. Here MET sec < 0 (M){\mathcal{MET}^{\,\,sec <0 }(M)} is the space of negatively curved metrics on M and T sec < 0 (M) = MET sec < 0 (M)/ DIFF0(M){\mathcal{T}^{\,\,sec <0 }(M) = \mathcal{MET}^{\,\,sec <0 }(M)/ {\rm DIFF}_0(M)} is, as defined in [FO2], the Teichmüller space of negatively curved metrics on M. In particular we conclude that T sec < 0 (M){\mathcal{T}^{\,\,sec <0 }(M)} is, in general, not connected. Two remarks: (1) the nontrivial elements in pkMET sec < 0 (M){\pi_{k}\mathcal{MET}^{\,\,sec <0 }(M)} constructed in [FO3] have trivial image by the map induced by MET sec < 0 (M)?T sec < 0 (M){\mathcal{MET}^{\,\,sec <0 }(M)\rightarrow\mathcal{T}^{\,\,sec <0 }(M)} ; (2) the nonzero classes in pkT sec < 0 (M){\pi_{k}\mathcal{T}^{\,\,sec <0 }(M)} constructed in [FO2] are not in the image of the map induced by MET sec < 0 (M)?T sec < 0 (M){\mathcal{MET}^{\,\,sec <0 }(M)\rightarrow\mathcal{T}^{\,\,sec <0 }(M)} ; the nontrivial classes in pkT sec < 0 (M){\pi_{k}\mathcal{T}^{\,\,sec <0 }(M)} given here, besides coming from MET sec < 0 (M){\mathcal{MET}^{\,\,sec <0 }(M)} and being harder to construct, have a different nature and genesis: the former classes – given in [FO2] – come from the existence
of exotic spheres, while the latter classes – given here – arise from the non-triviality and structure of certain homotopy
groups of the space of pseudo-isotopies of the circle
\mathbbS1{\mathbb{S}^1}. The strength of the new techniques used here allowed us to prove also a homology version of Theorem A, which is given in
Theorem B. 相似文献
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A compact set
K ì \mathbbCN{K \subset \mathbb{C}}^{N} satisfies (ŁS) if it is polynomially convex and there exist constants B,β > 0 such that
VK(z) 3 B(dist(z,K))b if dist(z,K) £ 1, \labelLS V_K(z)\geq B(\rm{dist}(z,K))^\beta\qquad \rm{ if}\quad \rm{ dist}(z,K)\leq 1, \label{LS} 相似文献
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Brian Osserman 《Mathematische Annalen》2006,336(4):963-986
Let C be a smooth curve, and M
r
(C) the coarse moduli space of vector bundles of rank r and trivial determinant on C. We examine the generalized Verschiebung map
induced by pulling back under Frobenius. Our main result is a computation of the degree of V
2 for a general C of genus 2, in characteristic p > 2. We also give several general background results on the Verschiebung in an appendix.This paper was partially supported by fellowships from the National Science Foundation and Japan Society for the Promotion of Sciences. 相似文献
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Xiaofei Song 《Linear algebra and its applications》2008,429(7):1579-1586
Let Mn be the algebra of all n×n complex matrices and Γn the set of all k-potent matrices in Mn. Suppose ?:Mn→Mn is a map satisfying A-λB∈Γn implies ?(A)-λ?(B)∈Γn, where A, B∈Mn, λ∈C. Then either ? is of the form ?(A)=cTAT-1, A∈Mn, or ? is of the form ?(A)=cTAtT-1, A∈Mn, where T∈Mn is an invertible matrix, c∈C satisfies ck=c. 相似文献
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该文中, a: X→Y, w: Y→ X为加法范畴 £ 中的态射, k1: K 1→X是(aw)i 的核, k2: K2 →Y是(wa)j 的核. 那么下列命题等价: (1) a 在 £ 中有w -加权Drazin逆a d,w; (2) 1:X→ L1是(aw)i 的上核,k1 1(aw)i+1}+ 1(k1 1)-1k1是可逆的; (3) 2: Y→ L2是(wa)j 的上核, k2 2和(wa)j+1+ 2(k2 2)-1k2是可逆的. 作者又研究了具有{1} -逆的正合加法范畴中态射的w -加权Drazin逆的柱心幂零分解, 证明了其存在性. 作者把具有核的态射的Drazin逆及其柱心幂零分解推广到具有核的态射的w -加权 Drazin逆及其柱心幂零分解, 并给出了表达式. 相似文献
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