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1.
\small\zihao{-5}\begin{quote}{\heiti 摘要:} 设$M$为$n+1$维单位球面$S^{n+1}(1)$中的一个极小闭超曲面,如果 $ n \le S \le n+\frac{2}{3}$, 则有 $S=n$ 且 $M$ 与某一Clifford 环面 $S^m(\sqrt{m/n}) \times S^{n-m}(\sqrt{(n-m)/n})$等距.  相似文献   

2.
In this note we define the property (ω′), a variant of Weyl’s theorem, and establish for a bounded linear operator defined on a Hilbert space the necessary and sufficient conditions for which property (ω′) holds by means of the variant of the essential approximate point spectrum σ1(·) and the spectrum defined in view of the property of consistency in Fredholm and index. In addition, the perturbation of property (ω′) is discussed.  相似文献   

3.

We introduce the notion of weighted limit in an arbitrary quasi-category, suitably generalizing ordinary limits in a quasi-category, and classical weighted limits in an ordinary category. This is accomplished by generalizing Joyal’s approach: we identify a meaningful construction for the quasi-category of weighted cones over a diagram in a quasi-category, whose terminal object is the weighted limit of the considered diagram. We then show that each weighted limit can be expressed as an ordinary limit. When the quasi-category arises as the homotopy coherent nerve of a category enriched over Kan complexes, we generalize an argument by Riehl-Verity to show that the weighted limit agrees with the homotopy weighted limit in the sense of enriched category theory, for which explicit constructions are available. When the quasi-category is complete, tensored and cotensored over the quasi-category of spaces, we discuss a possible comparison of our definition of weighted limit with the approach by Gepner-Haugseng-Nikolaus.

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4.
In this note we study the property (ω), a variant of Weyl's theorem introduced by Rakocevic, by means of the new spectrum. We establish for a bounded linear operator defined on a Banach space a necessary and sufficient condition for which both property (ω) and approximate Weyl's theorem hold. As a consequence of the main result, we study the property (ω) and approximate Weyl's theorem for a class of operators which we call the λ-weak-H(p) operators.  相似文献   

5.
In the note,we establish for a bounded linear operator defined on a Hilbert space the necessary and sufficient conditions for the stability of property(ω) by means of the variant of the essential approximate point spectrum and the induced spectrum of consistency in Fredholm and index.In addition,the stability of property(ω) for H(P) operators is considered.  相似文献   

6.
本文给出了强正则$(\alpha,\beta)-$族的概念,它是[4]和[5]中$SPG-$族概念的推广.进一步,给出了一种用强正则 $(\alpha,\beta)-$族构造强正则$(\alpha,\beta)-$几何的方法.另外,本文还证明了由强正则$(\alpha,\beta)-$线汇构造的强正则$(\alpha,\beta)-$几何是平移强正则$(\alpha,\beta)-$几何;当$t-r>\beta$时,反之亦成立.  相似文献   

7.
In this paper we construct a new quantum group Uq(osp(1,2,f)),which can be seen as a generalization of Uq(osp(1,2)).A necessary and sufficient condition for the algebra Uq(osp(1,2,f)) to be a super Hopf algebra is obtained and the center Z(Uq(osp(1,2,f))) is given.  相似文献   

8.
In this note we study the property(ω1),a variant of Weyl's theorem by means of the single valued extension property,and establish for a bounded linear operator defined on a Banach space the necessary and sufficient condition for which property(ω1) holds.As a consequence of the main result,the stability of property(ω1) is discussed.  相似文献   

9.
Let f_n be a non-parametric kernel density estimator based on a kernel function K and a sequence of independent and identically distributed random variables taking values in \mathbb{R}^d. In this paper we prove two moderate deviation theorems in L_1(\mathbb{R}^d) for \{f_n(x)-f_n(-x),\,n\ge1\}.  相似文献   

10.
  Qi  van Neerven  Jan 《Positivity》2019,23(1):11-19
Positivity - Let $$(A,{\mathscr {A}},\mu )$$ and $$(B,{\mathscr {B}},\nu )$$ be probability spaces, let $${\mathscr {F}}$$ be a sub- $$\sigma $$ -algebra of the product $$\sigma $$ -algebra...  相似文献   

11.
We briefly review previous work on the invariant theory of 3 ×  3 ×  3 arrays. We then recall how to generate arrays of arbitrary size \({m_1 \times \cdots \times m_k}\) with hyperdeterminant 0. Our main result is an explicit formula for the 3 ×  3 ×  3 hyperdeterminant as a polynomial in the fundamental invariants I 6, I 9, I 12 for the action of the Lie group \({SL_3(\mathbb{C}) \times SL_3(\mathbb{C}) \times SL_3(\mathbb{C})}\) . We apply our calculations to Nurmiev’s classification of normal forms for 3 ×  3 ×  3 arrays.  相似文献   

12.
We call T C B(H) consistent in Fredholm and index (briefly a CFI operator) if for each B ∈ B(H), TB and BT are Fredholm together and the same index of B, or not Fredholm together. Using a new spectrum defined in view of the CFI operator, we give the equivalence of Weyl's theorem and property (ω) for T and its conjugate operator T^*. In addition, the property (ω) for operator matrices is considered.  相似文献   

13.
In this paper, we study an important class of (α,β)-metrics in the form F = (α+β)^m+1/α^m on an n-dimensional manifold and get the conditions for such metrics to be weakly- Berwald metrics, where α = √aij(x)y^iy^j is a Riemannian metric and β = bi(x)y^i is a 1-form and m is a real number with m ≠ -1,0,-1/n. Furthermore, we also prove that this kind of (α,β)-metrics is of isotropic mean Berwald curvature if and only if it is of isotropic S-curvature. In this case, S-curvature vanishes and the metric is weakly-Berwald metric.  相似文献   

14.
有限维赋范空间至$C(\Om)$-的等   总被引:1,自引:0,他引:1  
詹大鹏 《数学学报》1998,41(1):177-184
本文讨论了有限维赋范空间X至无限维C(Ω)的等距逼近问题,证明了当X不足任意ln^∞(n∈N)的子空间且Ω中含无究多个孤立点时,等距逼近问题不成立;在其它情形该问题都成立。  相似文献   

15.
In the present paper, the interval-valued (∈,∈∨q)-fuzzy LI-ideal theory in lattice implication algebras is further studied. Some new properties of interval-valued (∈,∈∨q)-fuzzy LI-ideals are given. Representation theorem of interval-valued (∈,∈∨q)-fuzzy LI-ideal which is generated by an interval-valued fuzzy set is established. It is proved that the set consisting of all interval-valued (∈,∈∨q)-fuzzy LI-ideals in a lattice implication algebra, under the partial order ?, forms a complete distributive lattice.  相似文献   

16.
本文我们得到了$(\alpha,\beta)$-度量的测地系数$G^{i}(x,y)$和其逆$G^{i}(x,-y)$有相同Douglas曲率的充分必要条件.这个充分必要条件恰好是$(\alpha,\beta)$-度量具有可反测地线的充分必要条件.  相似文献   

17.
首先将软集的参数集赋予亚BCI-代数, 给出了亚BCI-代数的$(\alpha,\beta)$-软理想的概念.当$U=[0,1], \alpha=U, \beta=\phi$时,相应地就得到了亚BCI-代数的犹豫模糊理想的概念.研究了亚BCI-代数的$(\alpha,\beta)$-软理想的一些重要性质.最后讨论了亚BCI-代数的$(\alpha,\beta)$-软理想的同态像和原像的性质.  相似文献   

18.
19.
完全二部图Km,nKp,q-因子分解   总被引:2,自引:2,他引:0       下载免费PDF全文
杜北梁  王建 《中国科学A辑》2004,34(2):237-242
如果完全二部图Km,n的边集可以划分为Km,nKp,q-因子, 则称Km,n存在Kp,q-因子分解. 给出Km,n存在Kp,q-因子分解的一个充分条件. 同时证明: 对于任意正整数k, 当p:q = k:(k + 1)时, Km,n存在Kp,q-因子分解, 即Martin的BAC猜想成立.  相似文献   

20.
In this paper,necessary and sufficient conditions concerning the orthogonality and the composition of a couple of generalized (θ,φ)-derivations on a nonzero ideal of a semiprime ring are presented.These results are generalizations of several results of Breˇsar and Vukman,which are related to a theorem of Posner on the product of two derivations on a prime ring.  相似文献   

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