CAI 2009 was the Third International Conference on Algebraic Informatics. It was intended to
cover the topics of algebraic semantics on graphs and trees formalpowerseries syntacticobjects
algebraicpictureprocessing ?nite and- ?nite computations acceptors and transducers for strings
trees graphs arrays etc. decision problems algebraic characterization of logical theories
process algebra algebraic algorithms algebraic coding theory algebraicaspects of cr- tography.
CAI 2009 was dedicated to Werner Kuich on the occasion of his retirement.
ItwasheldinThessaloniki Greece duringMay19-22 2009andorganizedunder the auspices of the
Department of Mathematics of the Aristotle University of Thessaloniki. The opening lecture was
given by Werner Kuich the tutorials by Alessandra Cherubini and Wan Fokkink and the other
four invited lectures by Bruno Courcelle Dietrich Kuske Detlef Plump and Franz Winkler. This
volume contains 2 papers from the tutorials 5 papers of the invited lectures and 16
contributed papers. We received 25 submissions the contributors being from 14 and countries
and the Program Committee selected 16 papers.
WearegratefultothemembersoftheProgramCommitteefortheevaluation of the submissions and the
numerous referees who assisted in this work. We shouldliketo
thankallthecontributorsofCAI2009andespeciallythehonorary guest Werner Kuich and the invited
speakerswho kindly accepted our invitation to present their important work. Special thanks are
due to Alfred Hofmann the Editorial Director of LNCS who gave us the opportunity to publish
the proceedingsofourconferenceintheLNCSseries aswellastoAnnaKramerfrom Springer for the
excellent cooperation. We are also grateful to the members of the OrganizingCommittee and a
groupof graduatestudents who helped us with several organizing jobs.
