Let us say that a relation r is symmetric iff whenever x bears r to y, y bears r to x; otherwise, r is non-symmetric. In this paper, I will argue for the thesis that necessarily, there are no non-symmetric relations. What is this predicate ‘. . . bears . . . to . . . ’ in terms of which ‘symmetric’ was defined? According to one important theory of relations, this predicate is primitive, in the ...

We study theory revision and composition in the context of OLPFOL logic. In this logic, the representation of knowledge is split into two parts: writing definitions for completely known concepts (OLP part), and writing constraints and expressing partial knowledge on other concepts (FOL part). In a previous work, the composition of two OLP-FOL theories with nonintersecting sets of defined predic...

This paper presents two frameworks that generalize Conditional Preference networks (CP-nets). The first generalization is the LCP-theory, first order logic theory that provides a rich framework to express preferences. The the second generalization, the PCP-networks, is a probabilistic generalization of CP-nets that models conditional preferences with uncertainty.