SOFSEM 2010: Theory and Practice of Computer Science, 36th Conference on Current Trends in Theory and Practice of Computer Science, Spindleruv Ml'yn, Czech Republic, January 23-29, 2010. Proceedings (Jan van Leeuwen and Anca Muscholl and David Peleg and Jaroslav Pokorn'y and Bernhard Rumpe), volume 5901 of Lecture Notes in Computer Science, pages 503-514, 2010, Springer Verlag.