Description:An ideal text for researchers and professionals alike, this book constitutes the refereed proceedings of the 5th International Symposium on Foundations of Information and Knowledge Systems, FoIKS 2008 held in Pisa, Italy, in February 2008.The 13 revised full papers presented together with nine revised short papers and three invited lectures were carefully selected during two rounds of reviewing and improvement from 79 submissions.The papers deal comprehensively with foundational aspects of information and knowledge systems, including submissions from researchers working in fields such as discrete mathematics, logic and algebra, model theory, information theory, and complexity theory.They also feature papers submitted by those working in algorithmics and computation, geometry, analysis, statistics and optimization.All of the researchers here share a common trait: they are all interested in applying their ideas, theories and methods to research on information and knowledge systems.