This book constitutes the refereed proceedings of the 28th Conference on Current Trends in Theory and Practice of Informatics, SOFSEM 2001, held in Piestany, Slovak Republic, in November/December 2001.Teh volume presents 12 invited lectures and one keynote paper by leading researchers together with 18 revised full research papers selected from 46 submissions. The papers span the whole range of informatics with emphasis on trends in informatics, enabling technologies for global computing, and practical systems engineering.

This volume contains papers selected for presentation during the 24th Interna tional Symposium on Mathematical Foundations of Computer Science held on September 6-10, 1999 in Szklarska Por DEGREESba, Poland. The symposium, organized alternately in the Czech Republic, Slovakia, and Poland, focuses on theoretical aspects and mathematical foundations of computer science. The scientific program of the symposium consists of five invited talks given by Martin Dyer, Dexter Kozen, Giovanni Manzini, Sergio Rajsbaum, and Mads Tofte, and 37 accepted papers chosen out of 68 submissions. The volume contains all accepted contributed papers, and three invited papers. The contributed papers have been selected for presentation based on their scientific quality, novelty, and interest for the general audience of MFCS par ticipants. Each paper has been reviewed by at least three independent referees - PC members and/or sub-referees appointed by them. The papers were se lected for presentation during a fully electronic virtual meeting of the program committee on May 7, 1999. The virtual PC meeting was supported by software written by Artur Zgoda, Ph.D. student at the University of Wroclaw. The entire communication and access to quite a sensitive database at PC headquarters in Wroclaw was secured by cryptographic protocols based on technology of certificates.

This volume contains revised refereed versions of the best papers presented during the CSL '94 conference, held in Kazimierz, Poland in September 1994; CSL '94 is the eighth event in the series of workshops held for the third time as the Annual Conference of the European Association for Computer Science Logic.
The 38 papers presented were selected from a total of 151 submissions. All important aspects of the methods of mathematical logic in computer science are addressed: lambda calculus, proof theory, finite model theory, logic programming, semantics, category theory, and other logical systems. Together, these papers give a representative snapshot of the area of logical foundations of computer science.