Dihomotopic Reduction Used in Deadlock Detection

Deadlock detection for concurrent programs has traditionally been accomplished by symbolic methods or by search of a state transition system. We examine an approach that uses geometric semantics involving the topological notion of dihomotopy to partition the state-space into components, after which the reduced state-space is exhaustively searched. Prior work partitioned the state-space inductively, but in this paper we show that a recursive technique provides greater reduction of the size of the state transition system. As a result, we expect to see more efficient deadlock detection and eventually more efficient verification of some temporal properties for large problems if the partitioning can be done efficiently.