Author: lkoczy

Kóczy’s paper published in AnOR

Kóczy’s paper titled “Core-stability over networks with widespread externalities” has been published in the Annals of Operations Research.

The Covid-19 epidemic highlighted the significance of externalities: contacts with other people affect the chances of getting infected for our entire network. We study endogenous network formation where not only players or pairs but larger coalitions can, cooperatively change the network. We introduce a model for coalitional network stability for networks with widespread externalities. The network function form generalises the partition function form of cooperative games in allowing the network to be taken into account. The recursive core for network function form games generalises the recursive core for such environments. We present two simple examples to illustrate positive and negative externalities. The first is of a favour network and show that the core is nonempty when players must pay transfers to intermediaries; this simple setting also models economic situations such as airline networks. The second models social contacts during an epidemic and finds social bubbles as the solution.

Kóczy, L.Á. Core-stability over networks with widespread externalities. Ann Oper Res (2022). https://doi.org/10.1007/s10479-022-04669-5

Kóczy’s paper published in Games

Kóczy’s paper titled “Exits from the European Union and Their Effect on Power Distribution in the Council” (joint work with Dóra Gréta Petróczy and Mark Francis Rogers) has been published in Games.

Debates on an EU-leaving referendum arose in several member states after Brexit. This paper studies the effects of an additional exit on the power distribution in the Council of the European Union. Power indices of the member states are studied both with and without the country which might leave the union. Results show a pattern connected to a change in the number of states required to meet the 55% threshold. An exit that modifies this number benefits the countries with high population, while an exit that does not cause such a change benefits the small member states. According to the calculations, only the exit of Poland would be supported by the qualified majority of the Council.

Petróczy, D.G.; Rogers, M.F.; Kóczy, L.Á. Exits from the European Union and Their Effect on Power Distribution in the Council. Games 2022, 13, 18. https://doi.org/10.3390/g13010018

Postdoc openings at the QSMS (Q21)

The Faculty of Economic and Social Sciences (GTK) of the Budapest University of Technology and Economics (BME) invites applications for two full-time postdoctoral research positions at the Quantitative Social and Management Sciences Research Centre starting in the fall of 2022 at the latest.

Research Fields of interest: Game Theory, Evolutionary Game Theory, Signalling Theory, Reciprocity Theory, Economic Theory, Industrial Organization, Management, Platform Economics, Production Management, Operations Research, Social Choice Theory, Sustainable Development, Energy Economics, Apportionment, Network- and Experimental Economics and other quantitative fields and topics.

Applicants should have a PhD degree before taking up the position. The duration of the postdoctoral positions is three years and different schemes for tenure track can be offered. We offer favourable conditions regarding research facilities, data access, time devoted to research, travel support, etc. There will be an option to teach at the graduate level.

The Faculty of Economic and Social Sciences is the youngest faculty of the Budapest University of Technology and Economics comprising a great variety of departments and study programmes. BME is a widely-acclaimed institute of technology and the world’s oldest technical university celebrating its 240th academic year.

Application Procedure: Interviews will be conducted virtually, at the 4th EEA European Job Market for Economists, 15-18 December 2021. Applications consisting of a motivation letter, CV, 3 referee letters and the job market paper must be submitted online at https://econjobmarket.org/positions/7980.

Deadline: The search amongst applicants will start on 15 November 2021 and will continue until the positions are filled. For the job market, only applications received no later than 6 December 2021 will be considered.

Further information: Questions, but not applications, can be sent to egervari.zsuzsanna@gtk.bme.hu.

Koltai’s paper in the Int J Production Econ

Details | Universität Mannheim

The paper titled “An analysis of task assignment and cycle times when robots are added to human-operated assembly lines, using mathematical programming models” (joint with Dimény, I; Gallina, V; Gaal, A; and Sepe, C) has recently been published in the International Journal of Production Economics.

Assembly lines are flow-oriented production systems made up by a sequence of workstations arranged along a conveyor belt. In the “progressive assembly” manufacturing process, parts flow from station to station and components are gradually assembled together to obtain the final product. The assignment of tasks to the workstations is solved by assembly line balancing (ALB) problems. At each statin a worker is performing the assigned tasks. ALB problems can be formulated as by mixed integer linear mathematical programming models (MILP).

An extension to the classical ALP problems is when the different skills of workers are considered at task assignment. In this paper the possibility of the application of robots at the different stations is investigated. Robots are considered as workers with special skills, and the collaboration possibility of a robot and a worker at stations are also considered.

When workers and robots may collaborate at stations task assignment problem must be completed with the scheduling of task as well. This way the applied mathematical problem will be non-linear. The presented paper shows, how this type of models can be linearized or solved with constraint programming. The results may assist managers to find a proper assembly line configuration when workers as well as robots are used at the line.

Koltai, T; Dimény, I; Gallina, V; Gaal, A; Sepe, C: An analysis of task assignment and cycle times when robots are added to human-operated assembly lines, using mathematical programming models, International Journal of Production Economics, Volume 242, December 2021 (In-press). https://doi.org/10.1016/j.ijpe.2021.108292

Stody+games

Budapest, 6-7 October 2021

The aim of Stody+games, the Meeting on Games, Stochastics, and Dynamics is to bring together researchers who work on mathematical questions related to stochastic and dynamic features of games and to facilitate discussions and collaborations on this area. The meeting will include several talks and a poster session.

The workshop is co-hosted with Corvinus Center for Operations Research, Corvinus Institute for Advanced Studies, GAMENET, and Games Research Group Tel-Aviv University

Date: Wednesday+Thursday, 6+7 October 2021
Location: Corvinus University of Budapest, Budapest, Building E, Room 2001

Kóczy’s paper in Games

The paper titled Brexit and Power in the Council of the European Union discusses the impact of Brexit on voting in the Council of the European Union. There is a remarkably sharp relation between population size and the change in power: Brexit increases the largest members’ powers while decreasing the smallest ones’ powers. 

The paper is freely downloadable.