Solutions Based on Binary Semaphores

A graphical form of the mutual exclusion problem is considered in which each vertex represents a process and each edge represents a mutual exclusion constraint between the critical sections of the processes associated with its endpoints. An edge semaphore solution for mutual exclusion problems is defined, and those graphs which are edge solvable are characterized in terms of both a forbidden subgraph and a graph grammar. Finally, an efficient algorithm is given which generates the entry and exit sections for all processes in an edge-solv-