4 papers
Wreath products of distributive quasi relation algebra frames and their application to representability
Wilmari Morton, Claudette Robinson
We adapt a construction by Comer (1983) for polygroups to define the wreath product of the dual frames of two distributive quasi relation algebras satisfying certain conditions and…
Contractions of quasi relation algebras and applications to representability
Andrew Craig, Wilmari Morton, Claudette Robinson
Quasi relation algebras (qRAs) were first described by Galatos and Jipsen in 2013. They are generalisations of relation algebras and can also be viewed as certain residuated lattic…
Representability for distributive quasi relation algebras via nested sums
Andrew Craig, Claudette Robinson, Wilmari Morton
We extend the work of Galatos (2004) on nested sums, originally called generalised ordinal sums, of residuated lattices. We show that the nested sum of an odd quasi relation algebr…
Correspondence Theory for Many-valued Modal Logic
Cecelia Britz, Willem Conradie, Wilmari Morton
The aim of the present paper is to generalise Sahlqvist correspondence theory to the many-valued modal semantics defined by Fitting, assuming a perfect Heyting algebra as truth val…