This book constitutes the refereed proceedings of the 6th International Conference on Conceptual Structures, ICCS'98, held in Montpellier, France, in August 1998.The 20 revised full papers and 10 research reports presented were carefully selected from a total of 66 submissions;

Conceptual graph standard and extensions.- Matching in description logics: Preliminary results.- Ontologically yours.- Executing conceptual graphs.- From actors to processes: The representation of dynamic knowledge using conceptual graphs.- A semantic validation of conceptual graphs.- Using viewpoints and CG for the representation and management of a corporate memory in concurrent engineering.- WebKB-GE — A visual editor for canonical conceptual graphs.- Mapping of CGIF to operational interfaces.- TOSCANA-systems based on thesauri.- MULTIKAT, a tool for comparing knowledge of multiple experts.- A platform allowing typed nested graphs: How CoGITo became CoGITaNT.- Towards correspondences between Conceptual Graphs and Description Logics.- Piece resolution: Towards larger perspectives.- Triadic concept graphs.- Powerset trilattices.- Simple concept graphs: A logic approach.- Two FOL semantics for simple and nested conceptual graphs.- Peircean graphs for the modal logic S5.- Fuzzy order-sorted logic programming in conceptual graphs with a sound and complete proof procedure.- Knowledge querying in the conceptual graph model: The RAP module.- Stepwise construction of the Dedekind-MacNeille completion.- PAC learning conceptual graphs.- Procedural renunciation and the semi-automatic trap.- Ontologies and conceptual structures.- Manual acquisition of uncountable types in closed worlds.- A logical framework for modeling a discourse from the point of view of the agents involved in It.- Computational processing of verbal polysemy with conceptual structures.- Word graphs: The second set.- Tuning up conceptual graph representation for multilingual natural language processing in medicine.- Conceptual graphs for representing business processes in corporate memories.- Handling specification knowledge evolution using context lattices.- Using CG formal contexts to support business system interoperation.