On-line models for set-covering: the power of greediness

Minimum vertex covering is a famous combinatorial problem for which we know a polynomial time approximation algorithm (PTAA) with a ratio equal to 2, namely the maximal

Bounded cohomology, classifying spaces, flat bundles, Lie groups, subgroup distortion, stable commutator length, word metrics.. The authors are grateful to the ETH Z¨ urich, the MSRI

This paper contains three sections : in the first one, different solution techniques for the set covering problem are described ; this section may be skipped, as it is

In this section, we will give some properties of these Green functions that we will need later. The proof of the following lemma is based on elementary potential theory on the

But for finite depth foliations (which have two sided branching), there are many examples where it is impossible to make the pseudo-Anosov flow transverse to the foliation [Mo5] and

In the first part, by combining Bochner’s formula and a smooth maximum principle argument, Kr¨ oger in [15] obtained a comparison theorem for the gradient of the eigenfunctions,

First introduced by Faddeev and Kashaev [7, 9], the quantum dilogarithm G b (x) and its variants S b (x) and g b (x) play a crucial role in the study of positive representations

A second scheme is associated with a decentered shock-capturing–type space discretization: the II scheme for the viscous linearized Euler–Poisson (LVEP) system (see section 3.3)..