Predicate signature GraphPathSearchSig::start

The nodes that begin the search of the graph.

Ultimately, only paths from a start node to an end node will be found by this module.

In most cases, this will ideally be a smaller set of nodes than the end nodes. However, if the graph branches in one direction more than the other, a larger set which branches less may be preferable.

The design of this predicate has a great effect in how well this performance pattern will ultimately perform.