Synchronized counting method

A direct extension to the counting method is presented which can deal efficiently with both acyclic and cyclic relations. The extension to cycle cases, called the synchronized counting method, is simulated and studied using a Petri net model. Worst-case analysis shows that n/sup 2/ semijoin operations are required, where n is the number of nodes in the graph representing the relevant part of the input relations. The algorithm is shown to be sound and complete, and a comparison with other methods in the literature is included.<
>