CHR?: A flexible query language -- Query answering by means of diagram transformation -- Query subsumption -- Partial answers for unavailable data sources -- On diverse answers issued from flexible queries -- Answering queries in context -- Effective reformulation of Boolean queries with concept lattices -- Different ways to have something in common -- A schema-based approach to modeling and querying WWW data -- Querying multimedia documents by spatiotemporal structure -- Answers about validity and completeness of data: Formal definitions, usefulness and computation technique -- Progress report on the disjunctive deductive database system dlv -- A server for Fuzzy SQL queries -- Query answering in nondeterministic, nonmonotonic logic databases -- Optimization of logic queries with MIN and MAX predicates -- Searching for general documents -- Low retrieval remote querying dialogue with fuzzy conceptual, syntactical and linguistical unification -- Knowledge discovery for flexible querying -- Question answering with Textual CBR -- Using stem rules to refine document retrieval queries -- Application of fuzzy rule induction to data mining -- Applying genetic algorithms to the feature selection problem in information retrieval -- An overview of cooperative answering in databases -- Automatic generation of trigger rules for integrity enforcement in relational databases with view definition -- Estimating the quality of databases -- Querying clocked databases -- Querying for facts and content in hypermedia documents -- Querying objects with complex static structure -- An alternating well-founded semantics for query answering in disjunctive databases -- Towards a cooperative question-answering model -- Semantic query optimization through abduction and constraint handling -- Implementing fuzzy querying via the internet/WWW: Java applets, ActiveX controls and cookies.

This book constitutes the thoroughly refereed post-workshop proceedings of the Third International Conference on Flexible Query Answering Systems, FQAS'98, held in Roskilde, Denmark, in May 1998. The 32 revised papers presented were carefully reviewed and went through two rounds of selection for inclusion in the proceedings. This book is the first one focused on flexible query answering systems; this emerging area of research and development builts on results from mathematical logic, fuzzy logic, various database paradigms, information retrieval, linguistics, and human computer-interaction. The papers deal with issues occuring in querying databases and the Internet.