Bona, Glauber De
Towards a Unified Framework for Syntactic Inconsistency Measures
Bona, Glauber De (University of São Paulo) | Grant, John (University of Maryland) | Hunter, Anthony (University College London) | Konieczny, Sébastien (Université d'Artois)
A number of proposals have been made to define inconsistency measures. Each has its rationale. But to date, it is not clear how to delineate the space of options for measures, nor is it clear how we can classify measures systematically. In this paper, we introduce a general framework for comparing syntactic inconsistency measures. It uses the construction of an inconsistency graph for each knowledgebase. We then introduce abstractions of the inconsistency graph and use the hierarchy of the abstractions to classify a range of inconsistency measures.
Algorithms for Deciding Counting Quantifiers over Unary Predicates
Finger, Marcelo (University of Sao Paulo) | Bona, Glauber De (University College London)
We study algorithms for fragments of first order logic ex- tended with counting quantifiers, which are known to be highly complex in general. We propose a fragment over unary predicates that is NP-complete and for which there is a nor- mal form where Counting Quantification sentences have a single Unary predicate, thus call it the CQU fragment. We provide an algebraic formulation of the CQU satisfiability problem in terms of Integer Linear Programming based on which two algorithms are proposed, a direct reduction to SAT instances and an Integer Linear Programming version extended with a column generation mechanism. The latter is shown to lead to a viable implementation and experiments shows this algorithm presents a phase transition behavior.