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The QSMS Research Group organises research seminars on a regular basis with presentations by top researchers at an international level.

The seminars take place at 12:15-13:45 in room A406 in Building Q, Budapest University of Technology and Economics, Faculty of Economic and Social Sciences, Magyar tudósok körútja 2, 1117 Budapest. At the seminars sandwiches are provided. Please help the organisers by registering in advance.  Registration is free.

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

23 February: Maya Jalloul (QSMS seminar)

Presenting “Narrative adoption and strategic timing of disclosure?” at 16:00-17:30 online: Click here to join the meeting

On 23 February 2022, we have Maya Jalloul of Lebanese American University visiting us. She is going to give a seminar on “Narrative adoption and strategic timing of disclosure.” at 16:00 online Click here to join the meeting. Please help the organisers by registering in advance at egervari.zsuzsanna@gtk.bme.hu Registration is free. Event can only be attended with vaccination card.

Abstract: This paper investigates a model with two strategic politicians, a proponent and an opponent, and a group of non-strategic voters. The proponent, who is the first mover, has a narrative that she aims to convey to the voters; whereas the opponent’s objective is to divert the voters away from it. The strategic decision of the proponent is when to disclose her narrative with the objective to maximise the adoption of this narrative by a deadline, and that of the opponent is when to disclose the refutation. The voters opinions updating rule follows an average-based De Groot learning concept where a voter splits his attention between the two politicians, his own opinion and his neighbours. We show that once the proponent discloses her narrative, it is optimal for the opponent to disclose her refutation, and that the proponent faces a trade-off between early and late disclosure. We determine the optimal timing of disclosure for the cases of one voter and a group of voters and we examine connections among voters over a specific set of networks, while considering two types of voters, supporters and non-supporters. We also investigate the impact of homophily on timing of disclosure and we find that with higher homophily, the narrative adoption of the supporter is higher and that of the non-supporter is lower.

22 February: Christopher P. Stapenhurst (QSMS seminar)

Presenting “Can Media Pluralism Be Harmful to News Quality?” at 16:00-17:30 QA 406

On 22 February 2022, we have Chistopher P. Stapenhurst of University of Edinburgh visiting us. He is going to give a seminar on “Lemons by design: sowing secrets that curb corruption” (with Andrew Clausen) at 16:00 in room QA406. Please help the organisers by registering in advance at egervari.zsuzsanna@gtk.bme.hu Registration is free. Event can only be attended with vaccination card.

Abstract: We study a problem in which a polluting firm can bribe an inspector to conceal evidence of illegal behaviour. We find that the best way to deter bribes involves paying secret rewards and sending secret clues. The regulator promises to pay a secret reward to either the firm or the inspector when evidence is reported; it then gives them different clues about who will be rewarded. These clues are carefully constructed to engineer the worst possible lemons problem in the market for concealment: each player only wants to conceal evidence if they believe that the other player is more optimistic about being rewarded. But they cannot both be more optimistic in equilibrium, so no concealment takes place. As well as deterring bribes cheaply, this scheme demonstrates the full extent of contagious adverse selection in a bilateral trade environment.

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 202213, 18. https://doi.org/10.3390/g13010018

9 February: Federico Innocenti (QSMS Seminar)

(QSMS Seminar)

Presenting “Can Media Pluralism Be Harmful to News Quality?” at 16:00-17:30 online Click here to join the meeting

On 9 February 2022, we have Federico Innocenti of University of Mannheim visiting us. He is going to give a seminar on “Can Media Pluralism Be Harmful to News Quality?” at 16:00 online Click here to join the meeting. Please help the organisers by registering in advance at egervari.zsuzsanna@gtk.bme.hu Registration is free. Event can only be attended with vaccination card.

Abstract: I study a Bayesian persuasion model that connects two stylized facts characterizing the Internet: a great diversity of news sources and the proliferation of disinformation. I show that competition between news sources with opposite biases reduces information quality when news consumers have limited attention because of the endogenous formation of echo chambers. According to the standard narrative, echo chambers arise because news consumers exhibit confirmation bias. I show that even unbiased and rational news consumers devote their limited attention to like-minded news sources in equilibrium. Confirmation bias thus arises endogenously because news sources have no incentive to provide valuable information.

8 February: Giovanni Andreottola (QSMS Seminar)

Presenting “Polarization and Policy Design” at 16:00-17:30 in QA406.

On 8 February 2022, we have Giovanni Andreottola of University of Naples visiting us. He is going to give a seminar on “Polarization and Policy Design” at 16:00 in room A406 in Building Q, Budapest University of Technology and Economics, Faculty of Economic and Social Sciences, Magyar tudósok körútja 2, 1117 Budapest. Please help the organisers by registering in advance at egervari.zsuzsanna@gtk.bme.hu Registration is free. Event can only be attended with vaccination card.

Abstract: Voters in the U.S. and elsewhere have become highly polarized. How does this impact policymaking? We build a model to examine this question in the context of distributive politics and find that polarization can have a non-monotonic effect on equity. Political turnover and the inter-temporal resolution of policy uncertainty play key roles for this result. The implications of alternative electoral systems are also examined: contrary to conventional
wisdom, proportional systems may exacerbate partisan policymaking compared to majoritarian systems.

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