This book constitutes the refereed proceedings of the First International Conference of B and Z Users, ZB 2000, held in York, UK in August/September 2000.The 25 revised full papers presented together with four invited contributions were carefully reviewed and selected for inclusion in the book. The book documents the recent advances for the Z formal specification notion and for the B method; the full scope, ranging from foundational and theoretical issues to advanced applications, tools, and case studies, is covered. weiterlesen