关于Quotient Context of Morita Context的讨论

本文讨论了ＱｕｏｔｉｅｎｔＣｏｎｔｅｘｔｏｆ Ｍｏｒｉｔａ Ｃｏｎｔｅｘｔ的一些性质,并在此基础上证明：如果ＤＲ是一个完备Ｇａｂｒｉｅｌ拓扑,则一个（Ｐ,Ｑ）的商（Ｐ,Ｑ）作为Ｒ与Ｓ之间ＭＣ,它的商同构于（Ｐ,Ｑ）的一个商。     

A New BINOL-Derived Chiral Bifunctional Phosphine Organocatalyst: Preparation and Application in Asymmetric (Aza)-Morita-Baylis-Hillman Reactions

Abstract

A new BINOL-derived chiral bifunctional phosphine has been designed and successfully prepared, which features a cyclic substructure of 1,3,5-diazaphosphinane. This chiral phosphine possesses good air stability in solid state, and it can be conveniently used as a relatively more nucleophilic phosphine organocatalyst. Preliminary investigations showed that it could generally afford fair to excellent yields but only modest enantioselectivity in the (aza)-Morita–Baylis–Hillman reactions of activated olefins such as ethyl acrylate and methyl vinyl ketone with aldehydes or imines.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus Sulfer and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]     

Reaction of Aluminium Chloride with Benzo[C]- and Naphtho[2,3-C]pyrans

Aluminium(III) chloride is shown to cause (reversible) cis-trans stereoisomerisations in some benzo[c]- and naphtho[2,3-c]pyrans at ambient temperature.     

Glauberman对应诱导的Morita等价

假设G是一个p-可解群，A是一个可解群，它作用在G上且它的阶与G的阶互素，对适当的Dedekind整环R和RG的一个块B，A平凡地作用在它的某一个亏群上，我们证明B与它的Watanabe对应之间存在一个Morita等价．     

Maschke-type theorem and Morita context over weak Hopf algebras

This paper gives a Maschke-type theorem over semisimple weak Hopf algebras, extends the well-known Maschke-type theorem given by Cohen and Fishman and constructs a Morita context over weak Hopf algebras.     

Morita Duality for the Rings of Generalized Power Series

Let A, B be associative rings with identity, and (S, ≤) a strictly totally ordered monoid which is also artinian and finitely generated. For any bimodule _A M _B , we show that the bimodule _{[[ AS,≤ ]]}[M ^{S ,≤}]_{[[ BS, ≤ ]]} defines a Morita duality if and only if _A M _B defines a Morita duality and A is left noetherian, B is right noetherian. As a corollary, it is shown that the ring [[A ^{S ,≤}]] of generalized power series over A has a Morita duality if and only if A is a left noetherian ring with a Morita duality induced by a bimodule _A M _B such that B is right noetherian. Received April 13, 1999, Accepted December 12, 1999     

A partition-based approach towards constructing Galois (concept) lattices

Galois lattices and formal concept analysis of binary relations have proved useful in the resolution of many problems of theoretical or practical interest. Recent studies of practical applications in data mining and software engineering have put the emphasis on the need for both efficient and flexible algorithms to construct the lattice. Our paper presents a novel approach for lattice construction based on the apposition of binary relation fragments. We extend the existing theory to a complete characterization of the global Galois (concept) lattice as a substructure of the direct product of the lattices related to fragments. The structural properties underlie a procedure for extracting the global lattice from the direct product, which is the basis for a full-scale lattice construction algorithm implementing a divide-and-conquer strategy. The paper provides a complexity analysis of the algorithm together with some results about its practical performance and describes a class of binary relations for which the algorithm outperforms the most efficient lattice-constructing methods.     

Morita Equivalence of Fedosov Star Products and Deformed Hermitian Vector Bundles

Based on the usual Fedosov construction of star products for a symplectic manifold M, we give a simple geometric construction of a bimodule deformation for the sections of a vector bundle over M starting with a symplectic connection on M and a connection for E. In the case of a line bundle, this gives a Morita equivalence bimodule, and the relation between the characteristic classes of the Morita equivalent star products can be found very easily within this framework. Moreover, we also discuss the case of a Hermitian vector bundle and give a Fedosov construction of the deformation of the Hermitian fiber metric.     

Azumaya Categories

We define the notions of Azumaya category and Brauer group in category theory enriched over some very general base category V. We prove the equivalence of various definitions, in particular in terms of separable categories or progenerating bimodules. When V is the category of modules over a commutative ring R with unit, we recapture the classical notions of Azumaya algebra and Brauer group and provide an alternative, purely categorical treatment of those theories. But our theory applies as well to the cases of topological, metric or Banach modules, to the sheaves of such structures or graded such structures, and many other examples.