64 citations · 449 across the 29 of their papers we have counts for
29 papers
Perfect Copositive Matrices
Valentin Dannenberg, Achill Schürmann
In this paper we give a first study of perfect copositive matrices. They can be used to find rational certificates for completely positive matrices. We describe simila…
Sailing League Problems
Robert Schüler, Achill Schürmann
We describe a class of combinatorial design problems which typically occur in professional sailing league competitions. We discuss connections to resolvable block designs and equit…
A simplex algorithm for rational cp-factorization
Mathieu Dutour Sikirić, Achill Schürmann, Frank Vallentin
In this paper we provide an algorithm, similar to the simplex algorithm, which determines a rational cp-factorization of a given matrix, whenever the matrix allows such a factoriza…
Local Energy Optimality of Periodic Sets
Renaud Coulangeon, Achill Schürmann
We study the local optimality of periodic point sets in for energy minimization in the Gaussian core model, that is, for radial pair potential functions $f_c(r)=e^{-…
Local Formulas for Ehrhart Coefficients from Lattice Tiles
Maren H. Ring, Achill Schürmann
As shown by McMullen in 1983, the coefficients of the Ehrhart polynomial of a lattice polytope can be written as a weighted sum of facial volumes. The weights in such a local formu…
Equivalence of Lattice Orbit Polytopes
Frieder Ladisch, Achill Schürmann
Let be a finite permutation group acting on by permuting coordinates. A core point (for ) is an integral vector such that the convex hull…