Matthias Walter

h-index5
2papers

2 Papers

33.1OCApr 8
Relaxation strength for multilinear optimization: McCormick strikes back

Emily Schutte, Matthias Walter

We consider linear relaxations for multilinear optimization problems. In a recent paper, Khajavirad proved that the extended flower relaxation is at least as strong as the relaxation of any recursive McCormick linearization (Operations Research Letters 51 (2023) 146-152). In this paper we extend the result to more general linearizations, and present a simpler proof. Moreover, we complement Khajavirad's result by showing that the intersection of the relaxations of such linearizations and the extended flower relaxation are equally strong.

AIOct 23, 2025
A hybrid solution approach for the Integrated Healthcare Timetabling Competition 2024

Daniela Guericke, Rolf van der Hulst, Asal Karimpour et al.

We report about the algorithm, implementation and results submitted to the Integrated Healthcare Timetabling Competition 2024 by Team Twente, which scored third in the competition. Our approach combines mixed-integer programming, constraint programming and simulated annealing in a 3-phase solution approach based on decomposition into subproblems. Next to describing our approach and describing our design decisions, we share our insights and, for the first time, lower bounds on the optimal solution values for the benchmark instances. We finally highlight open problems for which we think that addressing them could improve our approach even further.