This paper presents an O(1.2738^k+kn)-time polynomial-space algorithm for Vertex Cover improving the previous O( 1.286^k) time upper bound by Chen, Kanj, and Jia.Expand

We show that the stretch factor of the Delaunay triangulation is less than $\rho = 1.998$, significantly improving the current best upper bound of 2.42 by Keil and Gutwin.Expand

This paper presents an O(1.2738k + kn)-time polynomial-space parameterized algorithm for Vertex Cover improving the previous O(2kk2k+2) time upper bound by Chen, Kanj, and Jia.Expand

We prove that the problem of deciding whether a given tree is contained inside a network is NP-complete and provide a parameterized algorithm that runs in time O(2^k^/^2n^2).Expand

We develop new techniques for deriving very strong computational lower bounds for a class of well-known NP-hard problems, including weighted satisfiability, dominating set, hitting set, set cover, clique, and independent set.Expand

A group of parameterized NP-hard problems, including weighted SAT, dominating set, hitting set, set cover, and feature set, cannot be solved in time n/sup o(k)/poly(m), where n is the size of the universal set from which the k elements are to be selected and m is the instance size, unless the first level W[l] of the W-hierarchy collapses to FPT.Expand

We prove that the stretch factor of the Delaunay triangulation of a set of points in the plane is less than ρ = 1.998, improving the previous best upper bound of 2.42.Expand