Mikhail V. Berlinkov. Approximating the Minimum Length of Synchronizing Words Is Hard. In Farid M. Ablayev, Ernst W. Mayr, editors, Computer Science - Theory and Applications, 5th International Computer Science Symposium in Russia, CSR 2010, Kazan, Russia, June 16-20, 2010. Proceedings. Volume 6072 of Lecture Notes in Computer Science, pages 37-47, Springer, 2010. [doi]
Abstract is missing.