@book{330b8c40c05744a8ae983b23130644a7,
title = "Directed paths with few or many colors in colored directed graphs",
abstract = "Given a graph $D=(V(D),A(D))$ and a coloring of $D$, not necessarily a proper coloring of either the arcs or the vertices of $D$, we consider the complexity of finding a path of $D$ from a given vertex $s$ to another given vertex $t$ with as few different colors as possible, and of finding one with as many different colors as possible. We show that the first problem is polynomial-time solvable, and that the second problem is NP-hard.",
keywords = "MSC-90C27, MSC-05C85, MSC-90C35",
author = "X. Li and S. Zhang and H.J. Broersma",
year = "2000",
language = "Undefined",
series = "Memorandum Faculteit TW",
publisher = "University of Twente, Department of Applied Mathematics",
number = "1543",
}