PP-2002-10: Venema, Yde (2002) Duals of subdirectly irreducible modal algebras. [Report]
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Abstract
We give a characterization of the simple, and of the subdirectly
irreducible boolean algebras with operators (including modal
algebras), in terms of the dual descriptive frame. These
characterizations involve a special binary \emph{quasi-reachability}
relation on the dual structure; we call a point $u$ a quasi-root of
the dual structure if every ultrafilter is quasi-reachable from $u$.
We prove that a boolean algebra with operators is simple iff every
point in the dual structure is a quasi-root; and that it is
subdirectly irreducible iff the collection of quasi-roots has measure
nonzero in the Stone topology on the dual structure.
| Item Type: | Report | 
|---|---|
| Report Nr: | PP-2002-10 | 
| Series Name: | Prepublication (PP) Series | 
| Year: | 2002 | 
| Uncontrolled Keywords: | boolean algebras with operators, modal logic, subdirectly irreducible algebras, simple algebras, duality | 
| Subjects: | Logic | 
| Date Deposited: | 12 Oct 2016 14:36 | 
| Last Modified: | 12 Oct 2016 14:36 | 
| URI: | https://eprints.illc.uva.nl/id/eprint/74 | 
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