3 citations · 8 across the 10 of their papers we have counts for
14 papers
Learning-Enhanced Neighborhood Selection for the Vehicle Routing Problem with Time Windows
Willem Feijen, Guido Schäfer, Koen Dekker +1
Large Neighborhood Search (LNS) is a universal approach that is broadly applicable and has proven to be highly efficient in practice for solving optimization problems. We propose t…
Round and Bipartize for Vertex Cover Approximation
Danish Kashaev, Guido Schäfer
The vertex cover problem is a fundamental and widely studied combinatorial optimization problem. It is known that its standard linear programming relaxation is integral for biparti…
Corruption in Auctions: Social Welfare Loss in Hybrid Multi-Unit Auctions
Andries van Beek, Ruben Brokkelkamp, Guido Schäfer
We initiate the study of the social welfare loss caused by corrupt auctioneers, both in single-item and multi-unit auctions. In our model, the auctioneer may collude with the winni…
Maximum Coverage with Cluster Constraints: An LP-Based Approximation Technique
Guido Schäfer, Bernard G. Zweers
Packing problems constitute an important class of optimization problems, both because of their high practical relevance and theoretical appeal. However, despite the large number of…
Cost Sharing over Combinatorial Domains: Complement-Free Cost Functions and Beyond
Georgios Birmpas, Evangelos Markakis, Guido Schäfer
We study mechanism design for combinatorial cost sharing. Imagine that multiple items or services are available to be shared among a set of interested agents. The outcome of a mech…
Budget-Feasible Mechanism Design for Non-Monotone Submodular Objectives: Offline and Online
Georgios Amanatidis, Pieter Kleer, Guido Schäfer
The framework of budget-feasible mechanism design studies procurement auctions where the auctioneer (buyer) aims to maximize his valuation function subject to a hard budget constra…
The Curse of Ties in Congestion Games with Limited Lookahead
Carla Groenland, Guido Schäfer
We introduce a novel framework to model limited lookahead in congestion games. Intuitively, the players enter the game sequentially and choose an optimal action under the assumptio…
Path deviations outperform approximate stability in heterogeneous congestion games
Pieter Kleer, Guido Schäfer
We consider non-atomic network congestion games with heterogeneous players where the latencies of the paths are subject to some bounded deviations. This model encompasses several w…
The Impact of Worst-Case Deviations in Non-Atomic Network Routing Games
Pieter Kleer, Guido Schäfer
We introduce a unifying model to study the impact of worst-case latency deviations in non-atomic selfish routing games. In our model, latencies are subject to (bounded) deviations…
Efficient Equilibria in Polymatrix Coordination Games
Mona Rahn, Guido Schäfer
We consider polymatrix coordination games with individual preferences where every player corresponds to a node in a graph who plays with each neighbor a separate bimatrix game with…
Coordination Games on Graphs
Krzysztof R. Apt, Bart de Keijzer, Mona Rahn +2
We introduce natural strategic games on graphs, which capture the idea of coordination in a local setting. We study the existence of equilibria that are resilient to coalitional de…
Bounding the Inefficiency of Altruism Through Social Contribution Games
Mona Rahn, Guido Schäfer
We introduce a new class of games, called social contribution games (SCGs), where each player's individual cost is equal to the cost he induces on society because of his presence.…
On the Inefficiency of Standard Multi-Unit Auctions
Bart de Keijzer, Evangelos Markakis, Guido Schäfer +1
We study two standard multi-unit auction formats for allocating multiple units of a single good to multi-demand bidders. The first one is the Discriminatory Auction, which charges…
Selfishness Level of Strategic Games
Krzysztof R. Apt, Guido Schaefer
We introduce a new measure of the discrepancy in strategic games between the social welfare in a Nash equilibrium and in a social optimum, that we call selfishness level. It is the…