We present a deterministic logspace algorithm for solving S-T Connectivity on directed graphs if (i) we are given a stationary distribution of the random walk on the graph in whic...
A homomorphism from an oriented graph G to an oriented graph H is a mapping from the set of vertices of G to the set of vertices of H such that ----(u)(v) is an arc in H whenever...
A tournament T = (V, A) is a directed graph in which there is exactly one arc between every pair of distinct vertices. Given a digraph on n vertices and an integer parameter k, th...
We show that every NP problem is polynomially equivalent to a simple combinatorial problem: the membership problem for a special class of digraphs. These classes are defined by me...
In this paper we consider the p-ary transitive reduction (TRp) problem where p > 0 is an integer; for p = 2 this problem arises in inferring a sparsest possible (biological) sig...