Processing math: 100%

Thursday, January 8, 2015

Hausdorffness and Regularity of Compact-Open C(X,Y) (7.46.6)

James Munkres Topology, chapter 7.46, exercise 6:

MathJax TeX Test Page Let C(X,Y) be under the compact-open topology. Show C(X,Y) is Hausdorff if Y is Hausdorff, and regular if Y is regular.

Proof: Hausdorffness is simple, as C(X,Y) inherits a topology at least as fine as that of a subspace under the product topology of YX, which is Hausdorff when Y is. So suppose Y is regular, let fC(X,Y), and let KC(X,Y) be a closed subset not containing f. Then there exists compact C1,...,CnX and open U1,...,UnY such that f(Ci)Ui and for all gK there exists ig such that g(Cig)Uig. Since f(Ci) is compact for each i, by regularity of Y choose neighborhoods Vi of these sets such that ¯ViUi. Then B(Ci,Vi) is a hood of f, and since ¯B(Ci,Vi)B(Ci,¯Vi) we observe ¯B(Ci,Vi)¯B(Ci,Vi)B(Ci,Ui) is disjoint from K. 

No comments:

Post a Comment