REDUCIBILITY IN SOME CATEGORIES OF PARTIAL RECURSIVE OPERATORS

We consider two categories with one object, namely the set of all partial functions of one variable from the set of natural numbers into itself; the morphisms are the partial recursive operators in one case, and certain continuous partial mappings in the other case. We show that these categories are recursion categories and we characterize the domains and the complete domains. Some observations are made on a notion of reducibility obtained by using the total morphisms of these categories, and, subsequently, the general recursive operators.     

Mackey systems of monoidal categories and G-spectra

We construct an equivariant infinite loop space machine denned on certain class of monoidal O _G -categories which have built-in Mackey structure. Applications include the equivariant infinite delooping of the classifying space BF(G) for stable spherical G-fibrations and also the construction of an infinite loop G-space E(X, G) with ₀ ^HE (X, G) naturally isomorphic to the equivariant Whitehead groups Wh _H (X) of given G-space X.Dedicated to Professor Shôrô Araki on his sixtieth birthday     

Coherent confluence modulo relations and double groupoids

A coherent presentation of an n-category is a presentation by generators, relations and relations among relations. Confluent and terminating rewriting systems generate coherent presentations, whose relations among relations are defined by confluence diagrams of critical branchings. This article introduces a procedure to compute coherent presentations when the rewrite relations are defined modulo a set of axioms. Our coherence results are formulated using the structure of n-categories enriched in double groupoids, whose horizontal cells represent rewriting paths, vertical cells represent the congruence generated by the axioms and square cells represent coherence cells induced by diagrams of confluence modulo. We illustrate our constructions on rewriting systems modulo commutation relations in commutative monoids, isotopy relations in pivotal monoidal categories, and inverse relations in groups.     

Analysis for the end of block wasted space

The problem examined in this report is the calculation of the average wasted space at the end of the block when variable length records are inserted in the file. Previous efforts are based in approximations. Here, a detailed analysis based on Markov chains gives the exact solution. A framework is presented which shows the relations between the previous approaches. The proposed model includes the previous models as special limiting cases. Simulation results close to the analytic results are also presented.This research was sponsored partially by the National Science Foundation under the grants DCR-86-16833, IRI-8719458 and IRI-8958546 and by the Air Force Office of Scientific Research under grant AFOSR-89-0303.     

The Category of Firm Modules for Nonunital Monomial Algebras

Let k be a field and X a set and P be a set of words over X. Consider the free nonunital k-algebra over X generated by the nonempty words over X and let R be the quotient of this algebra modulo the ideal generated by the words in P. R is called a “nonunital monomial algebra”. A right R-module M is said to be “firm” if M? _R R → M given by m ? r? mr is an isomorphism. In this article we prove that if R is a nonunital monomial algebra, the category of firm modules is Grothendieck.     

浅谈建筑防水材料的类别及施工注意事项

结合工作实践,在概述建筑防水材料类别的基础上,详细介绍了几种常用防水材料施工中的注意事项,对建筑防水材料施工的基本规定也作了阐述。     

计划与总结文体的异同辨析

阐述计划和总结都是机关单位或个人工作、学习和生活中的常用事务文书,其使用范围极为广泛。两种文体既有许多相同之处,在具体使用上也有明显的不同。如不注意,容易混淆。试对这两种文体的异同进行全面深入的比较辨析,以利于文体的实际运用,更好地发挥文体应有的效用。     

Girard Quantale范畴中的极限

本文讨论了Girard Quantale范畴中的极限,并且给出了该极限的结构,同时得到了此范畴是完备范畴,且具有拉回等性质.     

南阳市宛城区旅游资源调查与评价研究

根据《旅游资源分类、调查与评价》标准（GB/T18972—2003）对南阳市宛城区旅游资源进行实地调查、分类，并进行了定性与定量评价，发现宛城区旅游资源共有7个主类、20个亚类、50个基本类型．其中优良等级资源51个，普通等级资源78个．总体得分较高的类型为名人故居、人物等人文资源，由于保护不力、开发宣传不到位等原因，导致其单体平均分值较低．认为宛城区人丈旅游资源特色突出，应该加大对人文资源保护和开发力度，坚持以市场为导向，打响以商圣范蠡、医圣张仲景等名人文化为主的品牌，推进宛城区旅游的大发展．     

高校大类招生下学生专业选择的问题研究

近几年部分高校实施“大类招生”引起了不少考生的兴趣，也引起了高教界的关注。大类招生在强化基础教学、拓宽专业口径、培养创新型人才等方面都起到了很好的作用。本文研究了美国五大高校在专业设置和学生专业选择问题，并对基于本国国情大类招生下的学生专业选择措施及方法的探索性研究。