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Spatiality of countably presentable locales (proved with the Baire category theorem)

Published online by Cambridge University Press:  10 November 2014

REINHOLD HECKMANN*
Affiliation:
AbsInt Angewandte Informatik GmbH, Science Park 1, D-66123 Saarbrücken, Germany Email: heckmann@absint.com

Abstract

The first part of the paper presents a generalization of the well-known Baire category theorem. The generalization consists in replacing the dense open sets of the original formulation by dense UCO sets, where UCO means union of closed and open. This topological theorem is exactly what is needed to prove in the second part of the paper the locale-theoretic result that locales whose frame of opens has a countable presentation (countably many generators and countably many relations) are spatial. This spatiality theorem does not require choice.

Type
Paper
Copyright
Copyright © Cambridge University Press 2014 

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References

Davey, B. A. and Priestley, H. A. (2002) Introduction to Lattices and Order, 2nd edition, Cambridge University Press.Google Scholar
de Brecht, M. (2011) Quasi-Polish spaces. arXiv:1108.1445v1 [math.LO].Google Scholar
Escardó, M. (2003) Joins in the frame of nuclei. Applied Categorical Structures 11 (2) 117124.CrossRefGoogle Scholar
Fourman, M. P. and Grayson, R. (1982) Formal spaces. In: van Dalen, D. and Troelstra, A. (eds.) L.E.J. Brouwer Centenary Symposium. Proceedings of the Conference held in Noordwijkerhout, 8–13 June, 1981, Studies in Logic and the Foundations of Mathematics volume 110, North-Holland 107122.Google Scholar
Gierz, G., Hofmann, K. H., Keimel, K., Lawson, J. D., Mislove, M. and Scott, D. S. (2003) Continuous Lattices and Domains, Encyclopedia of Mathematics and its Applications volume 93, Cambridge University Press.Google Scholar
Heckmann, R. (1990) Power Domain Constructions, Ph.D. thesis, Universität des Saarlandes. (Available at http://rw4.cs.uni-sb.de/~heckmann/diss/diss.html.)Google Scholar
Herrlich, H. (1997) Choice principles in elementary topology and analysis. Commentationes Mathematicae Universitatis Carolinae 38 (3) 545552.Google Scholar
Johnstone, P. (1982) Stone Spaces, Cambridge University Press.Google Scholar
Kelley, J. L. (1955) General Topology. Springer-Verlag.Google Scholar
Valentini, S. (2006) Every countably presented formal topology is spatial, classically. Journal of Symbolic Logic 71 (2) 491500.Google Scholar
Vickers, S. J. (1989) Topology via Logic, Cambridge Tracts in Theoretical Computer Science volume 5, Cambridge University Press.Google Scholar
Vickers, S. J. (1993) Information systems for continuous posets. Theoretical Computer Science 114 (2) 201229.CrossRefGoogle Scholar
Vickers, S. J. (2005) Localic completion of generalized metric spaces I. Theory and Applications of Categories 14 328356.Google Scholar