Jens Vygen: [English Homepage] [Deutsche Homepage] [Publications] Projects [Students] [Courses] [Lectures] [Committees]

• Combinatorial optimization and approximation algorithms. Theory and algorithms for classical combinatorial optimization problems, e.g., related to network flows, shortest paths, Steiner trees, network design, submodular functions, facility location, multicommodity flows, resource sharing, disjoint paths, and the traveling salesman problem.
• Algorithms for chip design. Theoretical foundations and the design of better algorithms for important tasks in chip design, e.g., floorplanning, global and detailed placement, global and detailed routing, timing analysis and optimization, design of repeater trees and clock networks, logic optimization.
• Traveling salesman problem and vehicle routing. Theoretical foundations and design of better algorithms for variants of the traveling salesman problem, and various aspects related to complex real-world pickup and delivery vehicle routing problems.

Among the international cooperations and third-party funded projects, the following are most notable:

• a long standing and close cooperation with IBM on "Combinatorial Optimization and Chip Design". The algorithms and tools developed in this project (BonnTools) have been used for designing the most complex chips of many major technology companies, including all recent IBM microprocessors.
• a close cooperation with Deutsche Post DHL and Greenplan on "Combinatorial Optimization for Applications in Pickup and Delivery Services" (since 2017). See here and here.
• the research areas "Optimization in Large and Complex Networks" (2006-2012), "Algorithms, combinatorics, and complexity" (2012-2018) and "Combinatorial optimization, complexity, and chip design" (2019-2025) of the Hausdorff Center for Mathematics
• the long-term research project "Discrete Mathematics and Applications" of the Northrhine-Westphalian Academy of Sciences and Arts and the Union of the German Academies of Sciences (2004-2012)