Erratum: The Principal Maxmin Matrix Transversal Strategy

Erratum

The Complexity of MaxMin Length Triangulation

In 1991, Edelsbrunner and Tan gave an O(n) algorithm for finding the MinMax Length triangulation of a set of points in the plane. In this paper we resolve one of the open problems stated in that paper, by showing that finding a MaxMin Length triangulation is an NPcomplete problem. The proof implies that (unless P=NP), there is no polynomial-time approximation algorithm that can approximate the ...

Approximating the Maxmin-angle Covering Triangulation

Given a planar straight line graph we seek a covering triangulation whose minimumangle is as large as possible A covering triangulation is a Steiner triangulation with the following restriction No Steiner vertices may be added on an input edge We give an explicit upper bound on the largest possible minimum angle in any covering triangulation of a given input This upper bound depends only on loc...

Afriat from MaxMin

Afriat’s original method of proof is restored by using the minmax theorem.

Characterizations of Transversal and Fundamental Transversal Matroids

A result of Mason, as refined by Ingleton, characterizes transversal matroids as the matroids that satisfy a set of inequalities that relate the ranks of intersections and unions of nonempty sets of cyclic flats. We prove counterparts, for fundamental transversal matroids, of this and other characterizations of transversal matroids. In particular, we show that fundamental transversal matroids a...