This article focuses on polynomial approximation of optimization problems. The classical approximation classes (APX, PTAS,. . . ) have been structured by the introduction of approximation-preserving reductions and notions of completeness. For instance, natural problems are known to be APXor DAPX-complete (under the ∗ LAMSADE, Université Paris-Dauphine, 75775 Paris cedex 16, France. {bazgan,esco...

This paper describes a suite of extensions to the object oriented model, steering OO programming towards the Agent Programming paradigm; such set of extensions is called Agent Programming eXtensions (APX). APX has been specifically designed to leverage the development of agent-based systems, a widely adopted paradigm to model complex and dynamic software systems. A brief survey of the most comm...

Apixaban (APX) is a direct inhibitor of factor X (FXa) approved for prophylaxis and treatment of deep venous thrombosis and atrial fibrillation. Because FXa activates protease-activated receptor 2 (PAR-2) in endothelium and vascular smooth muscle, inhibition of FXa by APX may affect vasomotor function. The effect of APX was assessed in vitro, by wire myography, in rat mesenteric resistance arte...

To find evidence for a connection between heat stress response, oxidative stress, and common stress tolerance, we studied the effects of elevated growth temperatures and heat stress on the activity and expression of ascorbate peroxidase (APX). We compared wild-type Arabidopsis with transgenic plants overexpressing heat shock transcription factor 3 (HSF3), which synthesize heat shock proteins an...

A total vertex cover is a vertex cover whose induced subgraph consists of a set of connected components, each of which contains at least two vertices. The total vertex cover (TVC) problem ask for the total vertex cover with minimum cardinality. In this paper, we first show that the TVC problem is NP-complete for connected subcubic grid graphs of arbitrary large girth. Next, we show that the TVC...

We investigate the complexity of three optimization problems in Boolean propositional logic related to information theory: Given a conjunctive formula over a set of relations, find a satisfying assignment with minimal Hamming distance to a given assignment that satisfies the formula (NearestOtherSolution, NOSol) or that does not need to satisfy it (NearestSolution, NSol). The third problem asks...

The study of the approximability properties of NP-hard optimization problems has recently made great advances mainly due to the results obtained in the eld of proof checking. The last important breakthrough shows the APX-completeness of several important optimization problems is proved and thus reconciles`two distinct views of approximation classes: syntactic and computational'. In this paper w...

We study the approximation complexity of the Metric Dimension problem in bounded degree, dense as well as in general graphs. For the general case, we prove that the Metric Dimension problem is not approximable within (1 − ǫ) lnn for any ǫ > 0, unless NP ⊆ DTIME(nlog logn), and we give an approximation algorithm which matches the lower bound. Even for bounded degree instances it is APX-hard to d...

For a graph G = (V,E), a set D ⊆ V is called a semitotal dominating set of G if D is a dominating set of G, and every vertex in D is within distance 2 of another vertex of D. The Minimum Semitotal Domination problem is to find a semitotal dominating set of minimum cardinality. Given a graph G and a positive integer k, the Semitotal Domination Decision problem is to decide whether G has a semito...

In this paper we address a common question in wireless communication: How long does it take to satisfy an arbitrary set of wireless communication requests? This problem is known as the wireless scheduling problem. Our main result proves that wireless scheduling is in APX. In addition we present a robustness result, showing that constant parameter and model changes will modify the result only by...