Using functional magnetic resonance imaging (fMRI) we have evaluated the anatomical location of the motor hand area. The segment of the precentral gyrus that most often contained motor hand functionâ€¦ (More)

A graph G is given and two players, a cop and a robber, play the folioking game: the cop chooses a vertex, then the robber chooses a vertex, then the players move alternately beginning with the cop.â€¦ (More)

Let G be the digraph consisting of two oppositely-directed rings on the same set of n nodes. We provide a polynomialtime algorithm which, given a list of demands-each requiring a path from aâ€¦ (More)

We show that the problem of counting the number of linear extensions of a given partially ordered set is #P-complete. This settles a long-standing open question and contrssts with recent resultsâ€¦ (More)

17 There is one further consideration, which leads perhaps to the most intriguing conjecture of all. Let us put two tokens on a graph and let them take random walks, as before; but now suppose theâ€¦ (More)

The following problem arose in the planning of optical communications networks which use bidirectional SONET rings. Traffic demands di,j are given for each pair of nodes in an n-node ring; eachâ€¦ (More)

We consider simple means by which two people may determine whether they possess the same information without revealing anything else to each other in case

We model physical systems with ``hard constraints'' by the space Hom(G, H) of homomorphisms from a locally finite graph G to a fixed finite constraint graph H. For any assignment * of positive realâ€¦ (More)