Title
Varieties of Tense Algebras
Abstract
A b s t r a c t. The paper has two parts preceded by quite compre- hensive preliminaries. In the rst part it is shown that a subvariety of the variety T of all tense algebras is discriminator if and only if it is semisimple. The variety T turns out to be the join of an increasing chain of varieties Dn, which are discriminator varieties. The argument carries over to all nite type varieties of boolean algebras with operators satisfying some term conditions. In the case of tense algebras, the varieties Dn can be further characterised by certain natural conditions on Kripke frames. In the second part it is shown that the lattice of subvarieties of D0 has two atoms, the lattice of subvarieties of D1 has countably many atoms, and for n > 1, the lattice of subvarieties of Dn has continuum atoms. The proof of the second of the above statements involves a rather detailed description of zero-generated simple algebras in D1. Almost all the arguments are cast in algebraic form, but both parts begin with an outline describing their contents from the dual point of view of tense logics.
Year
Venue
Keywords
1998
Reports on Mathematical Logic
satisfiability,boolean algebra
Field
DocType
Volume
Interior algebra,Discrete mathematics,Algebra,Mathematics,Jordan algebra
Journal
32
Citations 
PageRank 
References 
14
1.54
6
Authors
1
Name
Order
Citations
PageRank
Tomasz Kowalski112424.06