FI MU Faculty of Informatics Masaryk University INFINITY 2002 Pre-Proceedings of 4th International Workshop on Veriﬁcation of Inﬁnite-State Systems by Anton´ ın Kuˇ cera Richard Mayr (Eds.) FI MU Report Series FIMU-RS-2002-04 Copyright c  2002, FI MU August 2002