摘要:

ABSTRACT:For a fixed‐point free continuous mapf: X → Xthere is studied the minimal size of an open (closed) coverPofXwithf(A) → A =Ø for anyA → P.Topological versions of some classical results of combinatorics ar

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55889.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT:A space isresolvableif it contains complementary dense subsets. Among the results proved here, are these. LetGi(1 ≤i≤ 6) be nondiscrete Hausdorff topological groups withGiAbelian (1 ≤i≤ 4),G3locally bounded,G4a Baire group, andG5totally bounded and uncountable. ThenG1×G2,G3,G4,G5, andG6×G6are r

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55890.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT:In this paperI‐open sets are used to introduce a new weak separation axiom and a new type of function. Some of the basic properties ofI‐Hausdorff spaces andI‐irresolute functions, as well as the connections between them are investi

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55891.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT:The functionf(n)= exp(ip(n)) is known to be distal on the group of the integers wheneverpis a real polynomial. We establish a simple criterion from which we deduce the following generalization:LetRbe a discrete ring,Xa character of the additive group ofR,andpa polynomial function onRand with coefficients inR. Then the functionf(s) =X(p(s)) is distal on the additive group ofR.

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55892.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55893.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT:M(G)is the set of all maximal complete subgraphs of a graphGwith a topology as a subset of the power set 2G. We characterize those Hausdorff spaces homeomorphic toM(G)for some graphGand call such spaces graph spaces. It follows from this characterization that every completely metrizable, zero dimensional space is a graph space. We characterize those graphsGfor whichM(L(G))is compact, whereL(G)is the line graph ofG. It is also shown that the topological product of graph spaces is a graph space.

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55894.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55895.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT:The recently formulated concept ofB‐spaces lies halfway between those of Morita'sM‐spaces and Ishii'sM*‐spaces on the one hand, and Nagami's Σ‐spaces on the other, and shares with them most of the properties that have come to be expected ofgeneralized metric spaces.We are to look into its stability with respect to the formation of countable products, sums, quasi‐perfect images and pre‐images and subspaces; the preservation of paracompactness over countable products within its confines and of course its

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55896.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT:In 1951, Katětov, in an article appearing in Fundamenta Mathematica, showed that each bounded uniformly continuous real‐valued function defined on a subspace (Y

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55897.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACT:Completion theory is established forT2filter spaces by adapting methods previously developed for Cauchy spaces.

ISSN:0077-8923    

DOI:10.1111/j.1749-6632.1995.tb55898.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY