mark@geier.philosophie.uni-stuttgart.de (Mark Johnson) (09/13/90)
Here's a question I'd like to throw out to the prolog community. The specific issue I'd like to raise is that it is difficult to find an efficent term representation of labelled cyclic graphs (for access and update). Representing the nodes of such a graph as a label and a list of edges, where an edge is a pair consisting of a label and a node, results in a ``cyclic structure'', with all the logical and implementational problems discussed in this newsgroup a while ago. And an obvious solution: to store the nodes in an array, and change the representation of an edge to be a pair consisting of a label and an index into this array, suffers from the lack of an efficient way of implementing for arrays. So how can cyclic graphs be efficiently implemented in Prolog? Suggestions welcome, Mark Johnson.