It is often convenient to maintain representations of distinguished subgraphs because they cannot be constructed on demand in a timely fashion. Furthermore, we may need to distinguish various combination of edges (tracks) between vertices (loci) according to the types o loci and use of tracks.
Because our application involves connecting loci of several LocusTypes, we must have terminology to discriminate between, say, the sequence of tracks to be taken between two friendly loci, passing through only friendly loci; and, the sequence of tracks to be taken between a friendly base firing on an enemy locus that is considered a target. Why? for the same reason that we differentiate between an interstate highway and a flight track. So, we will adopt the term route as a connected graph consisting of two or more distinct loci, and the set of tracks (edges) and loci (vertices) in between. Specifically, we may need to distinguish among various combinations of edges (tracks) between vertices (loci) according to LocusType and EnemyType or FriendType. However, Part 3 will address only a subset of possible route classes including, but not limited to, routes for military, civilian, and refugee movements; and trajectories for targeting purposes. Each class can be further partitionsed acccording to whether routes in the set are made of tracks between FriendlyLoci, or may involve one or more tracks connecting an EnemyLocus to a FriendlyLocus. Part 4 will add routes for managing weapons stores, and for distribution of essential supplies.