The Covid-19 epidemic highlighted the significance of externalities: contacts with other people do not only affect our chances of getting infected but also our entire network.

We introduce a model for coalitional network stability in networks with widespread externalities. The network function form generalises the partition function form of cooperative games in allowing the network structure to be taken into account. The recursive core for network function form games generalises the recursive core for such environments and its properties also rhyme with the corresponding inclusion properties of the optimistic and pessimistic recursive cores and can be seen as a modification of pairwise stability to a coalitional setting where the involvement of more players allows for the — partial — internalisation of the externalities, but we also allow residual players to endogenously respond to any externalities that may affect them. 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.

The Young Physicists Tournament is an established team-oriented scientific competition between high school students from 37 countries on 5 continents. The competition consists of scientific discussions called Fights. Three or four teams participate in each Fight, each of whom presents a problem while rotating the roles of Presenter, Opponent, Reviewer, and Observer among them.

The rules of a few countries require that each team announce in advance 3 problems they will present at the national tournament. The task of the organizers is to choose the composition of Fights in such a way that each team presents each of its chosen problems exactly once and within a single Fight no problem is presented more than once. Besides formalizing these feasibility conditions, in this paper we formulate several additional fairness conditions for tournament schedules. We show that the fulfillment of some of them can be ensured by constructing suitable edge colorings in bipartite graphs. To find fair schedules, we propose integer linear programs and test them on real as well as randomly generated data.

We develop a new model of social innovation (SI) inspired by the multi-channel interactive learning model of business innovation. As opposed to the linear models of innovation, this model does not identify ‘stages’ of business innovation. Rather, it stresses that innovation is an interactive process, in which collaboration among various partners are crucial, as they possess different types of knowledge, all indispensable for successful innovation activities.

Having considered numerous definitions of SI, first we propose a new one, then adapt the multi-channel interactive learning model to SI. To do so, we identify the major actors in an SI process, their activities, interactions, modes of (co-)producing, disseminating and utilising knowledge. We also consider the micro and macro environment of a given SI.

We illustrate the analytical relevance of the proposed model by considering three real-life cases. The model can assist SI policy-makers, policy analysts, as well as practitioners when devising, implementing or assessing SI.

A tanulmányban 38-41 európai ország lakosságának halálozásában tapasztalt eltérésekkel és ezek magyarázatával foglalkozom. Összehasonlítom a korai (0-64 éves kor)  és az időskori (65 év felett)  mortalitási rátákat alakító tényezőket betegség-csoportonként és nemek szerint a 2009. évre. Egy szűkebb mintán kitérek az elkerülhető (ezen belül a megelőzhető és kezelhető) betegségekből adódó halálozási különbségekre a 2015. évre.

Az alkalmazott modell az országok lakosságának életkörülményeit és életmódját veszi számításba, így az egy főre jutó GDP-t, a földrajzi elhelyezkedést, a légszennyezettséget, a népesség képzettségét, a dohányzási és égetettszesz fogyasztási szokásokat, valamint az egészségügyi kiadásokat.

A legmeghökkentőbb eredmény a légszennyezettség hatásával kapcsolatos: a tüdőrák esetében a 65 év alatti férfiaknál ennek mortalitást magyarázó, kiemelkedően magas súlya szinte megegyezik a leginkább ismert kockázati tényezőjével, a dohányzáséval; sőt, az időseknél már jelentős a különbség a légszennyezettség „javára”.

In cooperative games, the coalition structure core is, despite its potential emptiness, one of the most popular solutions. While it is a fundamentally static concept, the consideration of a sequential extension of the underlying dominance correspondence gave rise to a selection of non-empty generalizations. Among these, the payoff-equivalence minimal dominant set and the myopic stable set are defined by a similar set of conditions. We identify some problems with the payoff-equivalence minimal dominant set and propose an appropriate reformulation called the minimal dominant set. We show that replacing asymptotic external stability by sequential weak dominance leaves the myopic stable set unaffected. The myopic stable set is therefore equivalent to the minimal dominant set.

The nucleolus offers a desirable payoff-sharing solution in cooperative games, thanks to its attractive properties. Although computing the nucleolus is very challenging, the Kohlberg criterion offers a method for verifying whether a solution is the nucleolus in relatively small games (number of players n at most 15). This approach becomes more challenging for larger games as the criterion involves possibly exponentially large collections of coalitions, with each collection being potentially exponentially large. The aim of this work is twofold. First, we develop an improved Kohlberg criterion that involves checking the `balancedness’ of at most (n-1) sets of coalitions. Second, we exploit these results and introduce a novel descent-based constructive algorithm to find the nucleolus efficiently. We demonstrate the performance of the new algorithms by comparing them with existing methods over different types of games. Our contribution also includes the first open-source code for computing the nucleolus of moderately large games.

We study the effects of the geographic expansion of a Neonatal Intensive Care Unit (NICU) system and a Newborn Emergency Transportation System (NETS) on neonatal and infant mortality and long-term impairments. We utilize gradual expansion in Hungary, we use administrative and census data, and we identify the effects from longitudinal variation in access, using changing distance as an instrument. Improving access to delivering in a city with a NICU decreases 0-6-day mortality by 153/1000 (<1500g) and 24/1000 (<2500g). NETS effects are positive but smaller. Improved access saves lives in the long run, with zero overall effects on long-term impairments.

Using mortality registers and administrative data on incomes and population, we develop new evidence on the magnitudes and sources of life expectancy inequality in Hungary. We document considerable inequality across geographies and income groups, and show that inequality has increased between 1991-2016. We show that avoidable deaths play a large role in life expectancy inequality. Income-related geographic inequalities in health behaviors, access to care, and healthcare use are all strongly correlated with the inequality in life expectancy.

We estimate the effect of mass media coverage of the meningococcal disease on the uptake of meningococcal vaccinations in Hungary. Our analysis is based on administrative county-level data on vaccination purchases linked to indicators of media coverage of the meningococcal disease and to administrative records of disease incidence. Using geographical and time variations in these indicators, our fixed effects estimates indicate a strong positive effect of mass media coverage of the disease on the rate of vaccination with all types of the meningococcal vaccine. At the same time, we do not find evidence that disease incidence itself has a positive impact on vaccination. These findings are broadly in line with imperfect information and the principles of bounded rationality and highlight the responsibility of mass media in influencing health-related behaviours.

In this paper, we examine the relationship between temperature and human conception rates and project the impacts of climate change by the mid-twenty-first century. Using complete administrative data on 6.8 million pregnancies between 1980 and 2015 in Hungary, we show that exposure to hot temperatures reduces the conception rate in the first few weeks following the exposure, but a partial rebound is observed after that. Absent adaptation, climate change is projected to increase seasonal differences in conception rates, and a decline is expected in terms of annual conception rates. This latter decline is driven by a change in the number of induced abortions and spontaneous fetal losses. The overall number of live births is unaffected. However, some newborns may experience non-negligible consequences because of the altering in utero temperature exposure due to a shift in the timing of conception

Az innováció és a termelékenység közötti vállalati szintű kapcsolat elemzésekor az exporton kívül az importot is figyelembe kell venni. Az innováció pozitívan hat a termelékenységre, ugyanakkor a hatás mértéke időben változott. Az innováció termelékenységre kifejtett becsült hatása 2010-ig nőtt, utána csökkent és 2016-ra visszaesett a 2005. évi szintre. Ezt a hatást felerősítette az, hogy 2010 után folyamatosan és jelentősen csökkent az innovatív vállalatok aránya.

We allocate objects to agents as exemplified primarily by school choice. Welfare judgments of the object-allocating agency are encoded as edge weights in the acceptability graph.  The welfare of an allocation is the sum of its edge weights. We introduce the constrained welfare-maximizing solution, which is the allocation of highest welfare among the Pareto-efficient allocations. We identify conditions under which this solution is easily determined from a computational point of view. For the unrestricted case, we formulate an integer program and find this to be viable in practice as it quickly solves a real-world instance of kindergarten allocation and large-scale simulated instances. Incentives to report preferences truthfully are discussed briefly.