More puzzles than games, but many of the number puzzles published by Nikoli are quite mathematical in nature. They tend to involve an interplay between local and global conditions that have to be satisfied simultaneously, and one can glimpse geometric and graph-theoretic properties lurking. The...

Hypergraphs have been very useful algorithmically for the following "Steiner tree problem:" given a graph (V, E) with a specified "required/terminal" vertex subset R of V and a cost for each edge, find a minimum-cost set of edges which connects all the terminals (and includes whatever subset of V...