Lauerbach, Antonio - Chair of Computer Science I

Antonio Lauerbach

Lehrstuhl für Informatik I
Universität Würzburg
Am Hubland

97074 Würzburg

Deutschland

Building: M4

Room: 01.003

Phone: +49 931 31-80071

Email: antonio.lauerbach@uni-wuerzburg.de

ORCID: https://orcid.org/0009-0007-9093-3443

Research interests

Graph Theory
Complexity

Teaching

Winter Term 2025/26:

Exercises in Approximation Algorithms

TA

SS25: Algorithmische Graphentheorie
WS24/25: Algorithmen & Datenstrukturen
SS24: Graphen und diskrete Optimierung
WS23/24: Algorithmen & Datenstrukturen
SS23: Theoretische Informatik
WS22/23: Algorithmen & Datenstrukturen
SS22: Algorithmische Graphentheorie
WS21/22: Algorithmen & Datenstrukturen

Publications

2025[ to top ]

The Complexity of Counting Turns in the Line-Based Dial-a-Ride Problem. Lauerbach, Antonio; Reiter, Kendra; Schmidt, Marie. In SOFSEM 2025: Theory and Practice of Computer Science, Vol. 15539 of Lecture Notes in Computer Science, R. Královič, V. Kůrková (eds.), pp. 85–98. Springer Nature Switzerland, Cham, 2025.
- [ Abstract ]
- [ BibTeX ]
- [ DOI ]
- [ slides ]
- [ arxiv ]
Dial-a-Ride problems have been proposed to model the challenge to consolidate passenger transportation requests with a fleet of shared vehicles. The line-based Dial-a-Ride Problem (liDARP) is a variant where the passengers are transported along a fixed sequence of stops, with the option of taking shortcuts. In this paper we consider the liDARP with the objective function to maximize the number of transported requests. We investigate the complexity of two optimization problems: the liDARP, and the problem to determine the minimum number of turns needed in an optimal liDARP solution, called the MinTurn problem. Based on a number of instance parameters and characteristics, we are able to state the boundary between polynomially solvable and NP-hard instances for both problems. Furthermore, we provide parameterized algorithms that are able to solve both the liDARP and MinTurn problem.

@inproceedings{LauerbachRS25CountTurnsLiDARP, abstract = {Dial-a-Ride problems have been proposed to model the challenge to consolidate passenger transportation requests with a fleet of shared vehicles. The line-based Dial-a-Ride Problem (liDARP) is a variant where the passengers are transported along a fixed sequence of stops, with the option of taking shortcuts. In this paper we consider the liDARP with the objective function to maximize the number of transported requests. We investigate the complexity of two optimization problems: the liDARP, and the problem to determine the minimum number of turns needed in an optimal liDARP solution, called the MinTurn problem. Based on a number of instance parameters and characteristics, we are able to state the boundary between polynomially solvable and NP-hard instances for both problems. Furthermore, we provide parameterized algorithms that are able to solve both the liDARP and MinTurn problem.}, address = {Cham}, author = {Lauerbach, Antonio and Reiter, Kendra and Schmidt, Marie}, booktitle = {SOFSEM 2025: Theory and Practice of Computer Science}, editor = {Královič, Rastislav and Kůrková, Vera}, keywords = {myown}, pages = {85–98}, publisher = {Springer Nature Switzerland}, series = {Lecture Notes in Computer Science}, title = {The Complexity of Counting Turns in the Line-Based Dial-a-Ride Problem}, type = {Publication}, volume = 15539, year = 2025 }
Eliminating Majority Illusion. Fioravantes, Foivos; Lahiri, Abhiruk; Lauerbach, Antonio; Sabater, Lluís; Sieper, Marie Diana; Wolf, Samuel. In Proceedings of the 24th International Conference on Autonomous Agents and Multiagent Systems, of AAMAS ’25, pp. 749–757. International Foundation for Autonomous Agents and Multiagent Systems, Detroit, MI, USA, 2025.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
- [ arxiv ]
An opinion illusion refers to a phenomenon in social networks where agents may witness distributions of opinions among their neighbours that do not accurately reflect the true distribution of opinions in the population as a whole. A specific case of this occurs when there are only two possible choices, such as whether to receive the COVID-19 vaccine or vote on EU membership, which is commonly referred to as a majority illusion. In this work, we study the topological properties of social networks that lead to opinion illusions and focus on minimizing the number of agents that need to be influenced to eliminate these illusions. To do so, we propose an initial, but systematic study of the algorithmic behaviour of this problem.We show that the problem is NP-hard even for underlying topologies that are rather restrictive, being planar and of bounded diameter. We then look for exact algorithms that scale well as the input grows (FPT). We argue the in-existence of such algorithms even when the number of vertices that must be influenced is bounded, or when the social network is arranged in a ''path-like'' fashion (has bounded pathwidth). On the positive side, we present an FPT algorithm for networks with a ''star-like'' structure (bounded vertex cover number). Finally, we construct an FPT algorithm for ''tree-like'' networks (bounded treewidth) when the number of vertices that must be influenced is bounded. This algorithm is then used to provide a PTAS for planar graphs.

@inproceedings{FioravantesLLSSW25ElimMajorityIllusion, abstract = {An opinion illusion refers to a phenomenon in social networks where agents may witness distributions of opinions among their neighbours that do not accurately reflect the true distribution of opinions in the population as a whole. A specific case of this occurs when there are only two possible choices, such as whether to receive the COVID-19 vaccine or vote on EU membership, which is commonly referred to as a majority illusion. In this work, we study the topological properties of social networks that lead to opinion illusions and focus on minimizing the number of agents that need to be influenced to eliminate these illusions. To do so, we propose an initial, but systematic study of the algorithmic behaviour of this problem.We show that the problem is NP-hard even for underlying topologies that are rather restrictive, being planar and of bounded diameter. We then look for exact algorithms that scale well as the input grows (FPT). We argue the in-existence of such algorithms even when the number of vertices that must be influenced is bounded, or when the social network is arranged in a ''path-like'' fashion (has bounded pathwidth). On the positive side, we present an FPT algorithm for networks with a ''star-like'' structure (bounded vertex cover number). Finally, we construct an FPT algorithm for ''tree-like'' networks (bounded treewidth) when the number of vertices that must be influenced is bounded. This algorithm is then used to provide a PTAS for planar graphs.}, address = {Richland, SC}, author = {Fioravantes, Foivos and Lahiri, Abhiruk and Lauerbach, Antonio and Sabater, Lluís and Sieper, Marie Diana and Wolf, Samuel}, booktitle = {Proceedings of the 24th International Conference on Autonomous Agents and Multiagent Systems}, keywords = {networks}, pages = {749–757}, publisher = {International Foundation for Autonomous Agents and Multiagent Systems}, series = {AAMAS '25}, title = {Eliminating Majority Illusion}, year = 2025 }

Antonio Lauerbach

TA

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