This volume contains the texts of the tutorial lecture, five invited lectures and twenty short communications contributed for presentation at the Sixth International Meeting of Young Computer Scientists, IMYCS '90. The aim of these meetings is threefold: (1) to inform on newest trends, results, and problems in theoretical computer science and related fields through a tutorial and invited lectures delivered by internationally distinguished speakers, (2) to provide a possibility for beginners in scientific work to present and discuss their results, and (3) to create an adequate opportunity for...

The volume contains selected contributions from the scientific programme of the 5th International Meeting of Young Computer Scientists (IMYCS '88) held at Smolenice Castle (Czechoslovakia), November 14-18, 1988. It is divided into five chapters which approach the three crucial notions of contemporary theoretical computer science - machines, languages, and complexity - from different perspectives. The first chapter contains contributions dealing with problems of decidability, hierarchy, and complexity. Papers concerning different types and problems of automata theory form the second chapter....