The semicontinuous quasi-uniformity of a frame

The aim of this note is to show how various facts in classical topology connected with semicontinuous functions and the semicontinuous quasi-uniformity have their counterparts in pointfree topology. In particular, we introduce the localic semicontinuous quasi-uniformity, which generalizes the semico...

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Bibliographic Details
Main Author: Ferreira, Maria João (author)
Other Authors: Picado, Jorge (author)
Format: other
Language:eng
Published: 2003
Subjects:
Online Access:http://hdl.handle.net/10316/11427
Country:Portugal
Oai:oai:estudogeral.sib.uc.pt:10316/11427
Description
Summary:The aim of this note is to show how various facts in classical topology connected with semicontinuous functions and the semicontinuous quasi-uniformity have their counterparts in pointfree topology. In particular, we introduce the localic semicontinuous quasi-uniformity, which generalizes the semicontinuous quasiuniformity of a topological space (known to be one of the most important examples of transitive compatible quasi-uniformities). We show that it can be characterized in terms of the so called spectrum covers, via a construction introduced by the authors in a previous paper. Several consequences are derived.