Title of article :
Tightness, character and related properties of hyperspace topologies
Author/Authors :
Costantini، نويسنده , , Camillo and Hol?، نويسنده , , ?ubica and Vitolo، نويسنده , , Paolo، نويسنده ,
Issue Information :
دوماهنامه با شماره پیاپی سال 2004
Abstract :
Given a Hausdorff space X, we calculate the tightness and the character of the hyperspace CL∅(X) of X, endowed with either the co-compact or the lower Vietoris topology, and give some estimates for the tightness of CL∅(X), endowed with the Fell topology.
roperties related to first-countability and countable tightness, such as sequentiality, Fréchet property and, less directly, radiality and pseudoradiality, are investigated as well.
ry out our investigation, we also consider on the base space X several cardinal functions, and we compare some of them (which are newly defined or not so well known) with other classical ones, obtaining results and counterexamples which may be of some independent interest.
Keywords :
Radiality , k-netweight , (Hereditary) Lindelِf number , Pseudoradiality , (Hereditary) cofinal k-netweight , Tightness , Lower Vietoris topology , Fell topology , sequentiality , Compact cofinality , character , (Hereditary) k-Lindelِf number , Martinיs axiom , Co-compact topology , Fréchet property
Journal title :
Topology and its Applications
Journal title :
Topology and its Applications