Progress in Artificial Intelligence [electronic resource] : 6th Portuguese Conference on AI, EPIA '93 Porto, Portugal, October 6–8, 1993 Proceedings / edited by Miguel Filgueiras, Luís Damas.

Organizations as complex, dynamic design problems -- Specifying and verifying distributed Intelligent systems -- A logical approach for distributed truth maintenance -- Building text temporal structure -- Resolution of constraints in algebras of rational trees -- Inheritance in a hierarchy of theories -- Semantics of interworking knowledge based systems -- Combining terminological logics with tense logic -- Towards complete answers in concept languages -- Version space algorithms on hierarchies with exceptions -- Regular languages and a class of logic programs -- Some results on the complexity of SLD-derivations -- An or-parallel prolog execution model for a distributed shared memory machine -- Diagnosis and debugging as contradiction removal in logic programs -- Well-founded approximations of autoepistemic logic -- A process model for default logic and its realization in logic programming -- A unified approach to default reasoning and belief revision -- Second order E-matching as a tool for automated theorem proving -- Attribute-specific interchangeability in constraint satisfaction problems -- The use and interpretation of meta level constraints -- Preliminary formalization of an incremental hierarchical constraint solver -- Fast methods for solving linear diophantine equations -- A note on Chapman's Modal Truth Criterion -- Learning operators while planning -- Evaluating evidence for motivated discovery -- How to learn in an incomplete knowledge environment: Structured objects for a modal approach -- The semantics of rational contractions -- A uniform framework for Deductive Database derivation strategies -- Assumption set semantics (The procedures) -- Bargaining agents -- A constraint maintenance algorithm based on value propagation -- A text-to-phoneme translator for the Portuguese language -- Learning probabilistic models by conceptual pyramidal clustering.

This volume presents the proceedings of the 6th Portuguese Conference on Artificial Intelligence, EPIA '93, organized by the Portuguese Artificial Intelligence Association. Like the last two conferences in this series, it was run as an international event with strict requirements as to the quality of accepted submissions. Fifty-one submissions were receivedfrom 9 countries, the largest numbers coming from Portugal (18), Germany (10), and France (8). The volume contains 25 selected papers, together with 7 poster abstracts and one invited lecture: "Organizations as complex, dynamic design problems" by L. Gasser, I. Hulthage, B. Leverich, J. Lieb, and A. Majchrzak, all from the University of Southern California. The papersare grouped into parts on: distributed artificial intelligence, natural language processing, knowledge representation, logic programming, non-standard logics, automated reasoning, constraints, planning, and learning.