1. A method comprising: storing, in a data structure in a computing system, a plurality of sub-problems representing a main problem pertaining to an environment; constructing in the computing system for each of the sub-problems an abstract graph corresponding to each of the sub-problems; resolving at least a first abstract graph of the abstract graphs by decomposing one or more nodes of the first abstract graph; associating at least one of the one or more nodes of the first abstract graph with one or more nodes of others of the abstract graphs; and resolving at least one of the abstract graphs using information obtained by the association.