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101.
Libor Barto 《Journal of Pure and Applied Algebra》2007,211(3):721-731
A category is said to be alg-universal if every category of universal algebras can be fully embedded into it. We prove here that the category of varieties and interpretations, or in other words, the category of abstract clones and clone homomorphisms, is alg-universal. 相似文献
102.
A subgroup H of a finite group G is said to have the semi cover-avoiding property in G if there is a normal series of G such that H covers or avoids every normal factor of the series. In this paper, some new results are obtained based on the assumption that some subgroups have the semi cover-avoiding property in the group. 相似文献
103.
In this paper we first give a lower bound on multiplicities for Buchsbaum homogeneous k-algebras A in terms of the dimension d, the codimension c, the initial degree q, and the length of the local cohomology modules of A. Next, we introduce the notion of Buchsbaum k-algebras with minimal multiplicity of degree q, and give several characterizations for those rings. In particular, we will show that those algebras have linear free resolutions. Further, we will give many examples of those algebras. 相似文献
104.
Zero-schemes on smooth complex projective varieties, forcing all elements of ample and free linear systems to be reducible, are studied. Relationships among the minimal length of such zero-schemes, the positivity of the line bundle associated with the linear system, and the dimension of the variety are established. Bad linear spaces are also investigated. 相似文献
105.
In this paper, we establish a theorem on the distribution of primes in quadratic progressions on average. 相似文献
106.
C. Foias A. E. Frazho I. Gohberg M. A. Kaashoek 《Integral Equations and Operator Theory》1997,29(4):455-490
The family of all solutions of the three chains completion problem with a prescribed tolerance is described explicitly. It is shown that this family can be parameterized by a natural set of contractive upper triangular operators. As an application all solutions to a suboptimal nonstationary Nehari problem are described. 相似文献
107.
R. M. Dudley 《Probability Theory and Related Fields》1994,100(2):175-189
Summary In a separable metric space, if two Borel probability measures (laws) are nearby in a suitable metric, then there exist random variables with those laws which are nearby in probability. Specifically, by a well-known theorem of Strassen, the Prohorov distance between two laws is the infimum of Ky Fan distances of random variables with those laws. The present paper considers possible extensions of Strassen's theorem to two random elements one of which may be (compact) set-valued and/or non-measurable. There are positive results in finite-dimensional spaces, but with factors depending on the dimension. Examples show that such factors cannot entirely be avoided, so that the extension of Strassen's theorem to the present situation fails in infinite dimensions.This research was partially supported by a Guggenheim Fellowship, by National Science Foundation grant DMS 8505550 at MSRI-Berkeley, and other NSF grants 相似文献
108.
阐述了紫外无机非线性光学晶体分子工程学探索方法的基本特点,具体分析深紫外无机非线性光学晶体硼铍酸锶(SBBO)以氟硼铍酸钾(KBBF)为主要参考晶体的分子设计方法,随后根据晶体结构研究、单晶培养、和非线性光学性能测定等实验结果讨论SBBO作为新型深紫外无机晶体的主要优点,即它既具有更短的紫外吸收边(接近155nm)和较大的非线性光学系数(d22(SBBO)=06×d22(BBO)=138pm/V),同时晶体无明显层状习性,并肯有良好的化学稳定性和机械性能 相似文献
109.
Non-local approximation of the Mumford-Shah functional 总被引:3,自引:0,他引:3
The Mumford-Shah functional, introduced to study image segmentation problems, is approximated in the sense of -convergence by a sequence of non-local integral functionals.
Received June 6, 1996 / Accepted July 11, 1996 相似文献
110.
We consider a new method for producing intensity stabilization of cw lasers. This method incorporates negative feedback from a nonlinear saturable absorber to provide wideband noise-reduction and may produce an output beam for which shot noise is below the quantum limit. This new method can be used with a large variety of cw lasers and is particularly applicable to frequency-stabilized lasers which are locked to absorption lines.Permanent address: Institute of Laser Physics, Novosibirsk 630090, Russia 相似文献