Transition systems can be viewed either as process diagrams or as Kripke structures. The rst perspective is that of process theory, the second that of modal logic. This paper shows how various formalisms of modal logic can be brought to bear on processes. Notions of bisimulation can not only be motivated by operations on transition systems, but they can… (More)
With each projective geometry we can associate a Lyndon algebra. Such an algebra always satisfies Tarski's axioms for relation algebras and Lyndon algebras thus form an interesting connection between the fields of projective geometry and algebraic logic. In this paper we prove that if G is a class of projective geometries which contains an infinite… (More)
We consider n-ary relative products j n on subsets of a reeexive and symmetric binary relation and deene a variety of weakly associative relation algebras with polyadic composition operations (WA 1). A theorem that any A2 WA 1 is representable over a reeexive and symmetric relation is proved. We also show that the equational theory of WA 1 is decidable.