关于具有局部可数sn-网的空间

In this paper,spaces with a locally countable sn-network are discussed.It is shown that a space with a locally countable sn-network iff it is an snf-countable space with a locally countable k-network.As its application,almost-open and closed mappings(or finite-to-one and closed mapping) preserve locally countable sn-networks,and a perfect preimage theorem on spaces with a locally countable sn-network is established.     

拟第一可数空间和弱拟第一可数空间

讨论了拟第一可数空间和弱拟第一可数空间的遗传性和可积性,给出了一些反例来说明这两类空间在某些拓扑运算下的不封闭性,同时研究了它们具有遗传性和可积性的充要条件.     

星可数k网与序列覆盖s映射

证明了在空间具有星可数ｋ网的条件下,度量空间的１（２）序列覆盖ｓ映象是局部可分度量空间的１（２）序列覆盖、紧覆盖ｓ映象。     

可数Sober空间的若干性质北大核心

可数sober空间是sober空间的一种推广.本文讨论了可数sober空间的一些性质,特别地证明了以可数sober空间为对象、以连续映射为态射的范畴CSOB为完备范畴以及从任意空间到可数sober空间的连续映射空间为可数sober空间.     

一类g-第一可数空间的刻画

本文引进了弱开映射,利用它把一类ｇ－第一可数空间刻画为度量空间在不同弱开映射下的象,特别地,本文肯定回答了Ｈｏｓｈｉｎａ的一个问题。     

L—Fuzzy拓扑空间中的可数F紧性与几乎可数F紧性

本文在Ｌ－ｕｚｚｙ拓扑空间中引入可数Ｆ紧性与几乎可数Ｆ紧性的概念，并讨论了它们的性质及其相互关系。     

可数Fuzzy紧集的性质

讨论可数Fuzzy紧集在L值Zadeh型函数下的逆不变性,证明可数Fuzzy紧集与Fuzzy紧集的乘积是可数Fuzzy紧的。     

关于点可数序列邻域网

Ｉｔｉｓｋｎｏｗｎｔｏａｌｌｔｈａｔｔｈｅｔｈｅｏｒｙｏｆｔｈｅｐｏｉｎｔ－ｃｏｕｎｔａｂｌｅｃｏｖｅｒｓｂｅｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒ－ｔａｎｔｓｕｂｊｅｃｔｓｉｎＧｅｎｅｒａｌＴｏｐｏｌｏｇｙ．Ｔｈｅｐｏｉｎｔ－ｃｏｕｎｔａｂｌｅｃｏｖｅｒｓｗｉｔｈｖａｒｉｏｕｓｃｈａｒａｃｔｅｒｈａｖｅｂｅｅｎｄｉｓｃｕｓｓｅｄｂｙｍａｎｙｔｏｐｏｌｏｇｉｓｔｓ,ｓｕｃｈａｓＬｉｎａｎｄＴａｎａｋａ’ｓｐａｐｅｒ［１］ｏｎｐｏｉｎｔ－ｃｏｕｎｔａｂｌｅＫ－ｎｅｔｗｏｒｋ．Ｉｎｔｈｉｓｐａｐｅｒ,ｗ…     

序列网与度量空间的序列商映象──献给高国士教授80寿辰

本文定义了序列网的概念,建立了它与序列拟基、cs网之间的关系,获得了度量空间的确定商映象的一些新刻画．     

Inducing Measures by Cyclic Networks

Abstract

Measures on cyclic networks are defined in good agreement with basic homologic and measure-theoretic principles. A method to induce measures when the original network is reduced to smaller collections of circuits, is given as well.     

Winding Numbers and Average Frequencies in Phase Oscillator Networks

We study networks of coupled phase oscillators and show that network architecture can force relations between average frequencies of the oscillators. The main tool of our analysis is the coupled cell theory developed by Stewart, Golubitsky, Pivato, and Torok, which provides precise relations between network architecture and the corresponding class of ODEs in R^M and gives conditions for the flow-invariance of certain polydiagonal subspaces for all coupled systems with a given network architecture. The theory generalizes the notion of fixed-point subspaces for subgroups of network symmetries and directly extends to networks of coupled phase oscillators. For systems of coupled phase oscillators (but not generally for ODEs in R^M, where M ≥ 2), invariant polydiagonal subsets of codimension one arise naturally and strongly restrict the network dynamics. We say that two oscillators i and j coevolve if the polydiagonal θ_i = θ_j is flow-invariant, and show that the average frequencies of these oscillators must be equal. Given a network architecture, it is shown that coupled cell theory provides a direct way of testing how coevolving oscillators form collections with closely related dynamics. We give a generalization of these results to synchronous clusters of phase oscillators using quotient networks, and discuss implications for networks of spiking cells and those connected through buffers that implement coupling dynamics.     

(N)-空间和度量空间的mssc-映象

本用度量空间的mssc-映象给出了N-空间一些刻画，证明了空间X是N-空间当且仅当X是度量空间的序列覆盖(序列商)mssc-映象，肯定地回答了关于N-空间的一个猜想．     

集值映射空间在紧开拓扑下的N性质(英文)

本文研究了点紧连续集值映射族在紧开拓扑下的N性质.利用cs-σ网方法获得了如下结果:若X是N0空间,Y是N空间,则C_k(X,Y)是N空间.该结论将J.A.Guthrie关于单值连续映射空间的结论推广到了集值映射空间上,并且改进了相关结论.     

A note on the production of matroid minors

The circuits containing some fixed element of a connected matroid (such a collection is called a port) provide a matroid generalization of the “path collections” of graphs. In this note we show how to translate forbidden minor theorems in matroid theory into results about ports — and we find that many theorems are strengthened by such translation. Those collections of sets which are “path collections” of graphs may then be characterized.     

Comprehensive vs. comprehensible classifiers in logical analysis of data

The main objective of this paper is to compare the classification accuracy provided by large, comprehensive collections of patterns (rules) derived from archives of past observations, with that provided by small, comprehensible collections of patterns. This comparison is carried out here on the basis of an empirical study, using several publicly available data sets. The results of this study show that the use of comprehensive collections allows a slight increase of classification accuracy, and that the “cost of comprehensibility” is small.     

Curves on surfaces and surgeries

In this paper, we introduce a new surgery operation on the set of collections of curves, on a closed oriented surface, whose complement is a topological disk. We prove that any two such collections can be connected by a sequence of surgeries.