Publications by Nicolai Hähnle

On Sub-determinants and the Diameter of Polyhedra

Friedrich Eisenbrand, Nicolai Hähnle, Martin Niemeier, Nicolas Bonifas, Marco Di Summa

We derive a new upper bound on the diameter of a polyhedron , where . The bound is polynomial in and the largest absolute value of a sub-determinant of , denoted by . More precisely, we show that the diameter of is bounded by . If is bounded, then we show ...

Springer2014

Stable Routing And Unique-Max Coloring On Trees

Rico Zenklusen, Nicolai Hähnle, Laura Sanità

Some of the routing protocols used in telecommunication networks route traffic on a shortest path tree according to configurable integral link weights. One crucial issue for network operators is finding a weight function that ensures a stable routing: when ...

SIAM Publications2013

Testing additive integrality gaps

Friedrich Eisenbrand, Gennady Shmonin, Nicolai Hähnle

We consider the problem of testing whether the maximum additive integrality gap of a family of integer programs in standard form is bounded by a given constant. This can be viewed as a generalization of the integer rounding property, which can be tested in ...

Springer Berlin Heidelberg2013

On sub-determinants and the diameter of polyhedra

Friedrich Eisenbrand, Nicolai Hähnle, Martin Niemeier, Nicolas Bonifas, Marco Di Summa

2012

New Results in the Theory of Linear and Integer Programming

Nicolai Hähnle

The polynomial Hirsch conjecture states that the vertex-edge diameter of a d-dimensional polyhedron with n facets is bounded by a polynomial in d and n. For the special case where the polyhedron is defined as the set of points satisfying a system Ax ≤ b of ...

EPFL2012

Covering Cubes and the Closest Vector Problem

Friedrich Eisenbrand, Nicolai Hähnle, Martin Niemeier

We provide the currently fastest randomized (1+epsilon)-approximation algorithm for the closest vector problem in the infinity-norm. The running time of our method depends on the dimension n and the approximation guarantee epsilon by 2^(O(n))(log(1/epsilon ...

Acm Order Department, P O Box 64145, Baltimore, Md 21264 Usa2011

Scheduling periodic tasks in a hard real-time environment

Friedrich Eisenbrand, Nicolai Hähnle, Martin Niemeier

We give a rigorous account on the complexity landscape of an important real-time scheduling problem that occurs in the design of software-based aircraft control. The goal is to distribute tasks

\tau_i=(c_i,p_i)

on a minimum number of identical machines a ...

Springer-Verlag2010

Testing additive integrality gaps

Friedrich Eisenbrand, Gennady Shmonin, Doemoetoer Palvoelgyi, Nicolai Hähnle

We consider the problem of testing whether the maximum integrality gap of a family of integer programs in standard form is bounded by a given constant. This can be viewed as a generalization of the integer rounding property, which can be tested in polynomi ...

2010

Diameter of Polyhedra: Limits of Abstraction

Friedrich Eisenbrand, Thomas Rothvoss, Nicolai Hähnle

We investigate the diameter of a natural abstraction of the 1-skeleton of polyhedra. Although this abstraction is simpler than other abstractions that were previously studied in the literature, the best upper bounds on the diameter of polyhedra continue to ...

2009