We show that strict deterministic propositional dynamic logic with intersection is highly
undecidable, solving a problem in the Stanford Encyclopedia of Philosophy. In fact we show …

An EQ-monoid A is a monoid with distinguished subsemilattice L with 1 2 L and such that
any a, b 2 A have a largest right equalizer in L. The class of all such monoids equipped with …

We define interior algebras, which are natural generalizations of Boolean rings equipped
with an interior operator and of equality algebras. We characterize interior algebras in terms …

We consider universal algebras which are monoids and which have a binary operation we
call internalized equality, satisfying some natural conditions. We show that the class of such …

Two propositions may be regarded as doxastically equivalent if revision of an agent's beliefs
to adopt either has the same effect on the agent's belief state. We enrich the language of …

The agreement quasi-order on pairs of (partial) transformations on a set X is defined as
follows:(f, g) ⪯ (h, k) if whenever f, g are defined and agree, so do h, k. We axiomatize …

We show that equality may be internalized in Boolean algebras, in a number of possible
ways, as a binary operation satisfying reflexivity and replacement properties. The variety of …

This paper reports the implementation of a system for the creation of rational automata:
automata that communicate with one another, display curiosity, learn and are creative. The …

Central internal algebras and varieties Page 1 COMMUNICATIONS IN ALGEBRA, 27(8),
3851-3862 (1999) CENTRAL INTERNAL ALGEBRAS AND VARIETIES AV Kelarev and T …

If X is a set, the fix-set quasiorder on a group of permutations of X is the quasiorder induced
by containment of the fix-sets of elements of SX. Axioms for such quasiorders on groups …