5 papers
Extending Exact Integrality Gap Computations for the Metric TSP
William Cook, Stefan Hougardy, Moritz Petrich
The subtour relaxation of the traveling salesman problem (TSP) plays a central role in approximation algorithms and polyhedral studies of the TSP. A long-standing conjecture assert…
Local elimination in the traveling salesman problem
William Cook, Keld Helsgaun, Stefan Hougardy +1
Hougardy and Schroeder (WG 2014) proposed a combinatorial technique for pruning the search space in the traveling salesman problem, establishing that, for a given instance, certain…
On a symmetry of the category of integrable modules
William J. Cook, Christopher Sadowski
Haisheng Li showed that given a module (W,Y_W(\cdot,x)) for a vertex algebra (V,Y(\cdot,x)), one can obtain a new V-module W^Δ = (W,Y_W(Δ(x)\cdot,x)) if Δ(x) satisfies certain natu…
A recurrence relation for characters of highest weight integrable modules for affine Lie algebras
William J. Cook, Haisheng Li, Kailash C. Misra
Using certain results for the vertex operator algebras associated with affine Lie algebras we obtain recurrence relations for the characters of integrable highest weight irreducibl…
On the Constructive Inverse Problem in Differential Galois Theory
William J. Cook, Claude Mitschi, Michael F. Singer
We give sufficient conditions for a linear differential equation to have a given semisimple group as its Galois group. For any linear algebraic group G given as a semidirect produc…