Estudio coalicional de los parlamentos autonómicos españoles de régimen común

Se analiza la distribución de poder entre los partidos políticos que obtuvieron representación en las elecciones celebradas el 26 de mayo de 1991 para renovar los Parlamentos de las trece Comunidades Autónomas de Régimen Comun. Se usan dos medidas numéricas de poder: el índice de Shapley-Shubik para juegos simples y su generalización, el valor coalicional de Owen para juegos con estructura de coaliciones. Las coaliciones previstas segun el criterio de optimización del valor coalicional coinciden notablemente con las formadas en cada Comunidad Autónoma

Assessment of the influence of features on a classification problem: an application to COVID-19 patients

This paper deals with an important subject in classification problems addressed by machine learning techniques: the evaluation of the influence of each of the features on the classification of individuals. Specifically, a measure of that influence is introduced using the Shapley value of cooperative games. In addition, an axiomatic characterisation of the proposed measure is provided based on properties of efficiency and balanced contributions. Furthermore, some experiments have been designed in order to validate the appropriate performance of such measure. Finally, the methodology introduced is applied to a sample of COVID-19 patients to study the influence of certain demographic or risk factors on various events of interest related to the evolution of the diseaseThe authors are grateful to Ricardo Cao Abad and to the Dirección Xeral de Saúde Pública of the Xunta de Galicia in Spain. This work has been supported by the ERDF, the Government of Spain/AEI [grants MTM2017-87197-C3-1-P and MTM2017-87197-C3-3-P]; the Xunta de Galicia [Grupos de Referencia Competitiva ED431C2016-015, ED431C2017/38, and ED431C 2021/24, and Centro Singular de Investigación de Galicia ED431G/01]; and by the collaborative research project of the IMAT “Mathematical, statistical and dynamic study of the epidemic COVID-19”, subsidized by the Vice-Rector’s Office for Research and Innovation at the University of Santiago de Compostela, Spain. The research of Laura Davila-Pena has been funded by the Government of Spain [grant FPU17/02126]. We would also like to thank the three anonymous referees and the editor for their constructive comments and suggestions, which helped us to improve the final version of this paperS

Assessment of the Influence of Features on a Classification Problem: An Application to COVID-19 Patients

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] This paper deals with an important subject in classification problems addressed by machine learning techniques: the evaluation of the influence of each of the features on the classification of individuals. Specifically, a measure of that influence is introduced using the Shapley value of cooperative games. In addition, an axiomatic characterisation of the proposed measure is provided based on properties of efficiency and balanced contributions. Furthermore, some experiments have been designed in order to validate the appropriate performance of such measure. Finally, the methodology introduced is applied to a sample of COVID-19 patients to study the influence of certain demographic or risk factors on various events of interest related to the evolution of the disease.The authors are grateful to Ricardo Cao Abad and to the Dirección Xeral de Saúde Pública of the Xunta de Galicia in Spain. This work has been supported by the ERDF, the Government of Spain/AEI [grants MTM2017-87197-C3-1-P and MTM2017-87197-C3-3-P]; the Xunta de Galicia [Grupos de Referencia Competitiva ED431C2016-015, ED431C2017/38, and ED431C 2021/24, and Centro Singular de Investigación de Galicia ED431G/01]; and by the collaborative research project of the IMAT “Mathematical, statistical and dynamic study of the epidemic COVID-19”, subsidized by the Vice-Rector’s Office for Research and Innovation at the University of Santiago de Compostela, Spain. The research of Laura Davila-Pena has been funded by the Government of Spain [grant FPU17/02126]Xunta de Galicia; ED431C2016-015Xunta de Galicia; ED431C2017/38Xunta de Galicia; ED431C 2021/24Xunta de Galicia; ED431G/0

The effect of valence and ideology in campaign conversion : panel evidence from three Spanish general elections

This paper studies changes in voting preferences over election campaigns. Building on the literature on spatial models and valence issues, we study whether (1) ideological distance to political parties, (2) assessments of party competence to handle different policy issues, and (3) voter-updated candidate evaluations are factors that explain shifts in voter choices in the weeks preceding the election. To test our hypotheses, we use data from three survey panels conducted for the 2008, 2011 and 2015 Spanish general elections. Our findings show that valence factors are more influential than ideological indifference to account for campaign conversion

Allocating Campaign Effort in Spain: Evidence from Four General Elections

This paper analyses which districts are targeted by Spanish political parties in their electoral campaigns. We find that the major Spanish parties - PP and PSOE - mobilise districts where they are more likely to win a new seat or are in danger of losing one they already hold. The predicted closeness of the district race is more relevant in the smallest districts. We also find that Spanish parties mobilise their strongholds. We suggest that, apart from the pure office-seeking strategies, political finance motivations might also play a role in the mobilisation choices made by Spanish party elites

The proportional partitional Shapley value

A new coalitional value is proposed under the hypothesis of isolated unions. The main difference between this value and the Aumann–Drèze value is that the allocations within each union are not given by the Shapley value of the restricted game but proportionally to the Shapley value of the original game. Axiomatic characterizations of the new value, examples illustrating its application and a comparative discussion are provided.Peer ReviewedPostprint (author’s final draft

Evaluating the impact of items and cooperation in inventory models with exemptable ordering costs

In this paper we introduce and analyse, from a game theoretical perspective, several multi-agent or multi-item continuous review inventory models in which the buyers are exempted from ordering costs if the price of their orders is greater than or equal to a certain amount. For all models we obtain the optimal ordering policy. We first analyse a simple model with one firm and one item. Then, we study a model with one firm and several items, for which we design a procedure based on cooperative game theory to evaluate the impact of each item on the total cost. Then, we deal with a model with several firms and one item for each firm, for which we characterise a rule to allocate the total cost among the firms in a coalitionally stable way. Finally, we discuss a model with several firms and several items, for which we characterise a rule to allocate the total cost among the firms in a coalitionally stable way and to evaluate the impact of each item on the cost that would be payable to each firm when using the allocation rule. All the concepts and results of this article are illustrated using data from a case study.Agencia Estatal de Investigación | Ref. MTM2017-87197-C3-1-PAgencia Estatal de Investigación | Ref. MTM2017-87197-C3-2-PAgencia Estatal de Investigación | Ref. PGC2018-097965-B-I00Agencia Estatal de Investigación | Ref. PID2021-124030NB-C31Agencia Estatal de Investigación | Ref. PID2021-124030NB-C33MCIN/AEI/10.13039/501100011033/ | Ref. PID2022-137211NB-100Comunidad Valenciana | Ref. PROMETEO/2021/063Xunta de Galicia | Ref. ED431C-2020/03Xunta de Galicia | Ref. ED431C-2020/14Universidade da Coruña/CISU

Cooperation on capacitated inventory situations with fixed holding costs

[Abstract] In this paper we analyze a situation in which several firms deal with inventory problems concerning the same type of product. We consider that each firm uses its limited capacity warehouse for storing purposes and that it faces an economic order quantity model where storage costs are irrelevant (and assumed to be zero) and shortages are allowed. In this setting, we show that firms can save costs by placing joint orders and obtain an optimal order policy for the firms. Besides, we identify an associated class of costs games which we show to be concave. Finally, we introduce and study a rule to share the costs among the firms which provides core allocations and can be easily computed.Ministerio de Ciencia e Innovación; MTM2011-23205Galicia. Consellería de Economía e Industria; INCITE09-207-064-PRComunidad Valenciana. Generalidad; ACOMP/2014Ministerio de Ciencia e Innovación; MTM2011-27731-C0

On benefits of cooperation under strategic power

We introduce a new model involving TU-games and exogenous structures. Specifically, we consider that each player in a population can choose an element in a strategy set and that, for every possible strategy profile, a TU-game is associated with the population. This is what we call a TU-game with strategies. We propose and characterize the maxmin procedure to map every game with strategies to a TU-game. We also study whether or not the relevant properties of TU-games are transmitted by applying the maxmin procedure. Finally, we examine two relevant classes of TU-games with strategies: airport and simple games with strategies.Ministerio de Economía y Competitividad | Ref. PGC2018-097965-B-100Ministerio de Economía y Competitividad | Ref. MTM2017-87197-C3-1-PMinisterio de Economía y Competitividad | Ref. MTM2017-87197-C3-2-PMinisterio de Economía y Competitividad | Ref. MTM2014-53395-C3-1-PMinisterio de Economía y Competitividad | Ref. MTM2014-53395-C3-3-PMinisterio de Economía y Competitividad | Ref. MTM2014-54199-PXunta de Galicia | Ref. ED431C-2016-015Xunta de Galicia | Ref. ED431C-2016-040Xunta de Galicia | Ref. ED431G/0

Allocation Rules for Games with Optimistic Aspirations

A game with optimistic aspirations specifies two values for each coalition of players: the first value is the worth that the players in the coalition can guarantee for themselves in the event that they coordinate their actions, and the second value is the amount that the players in the coalition aspire to get under reasonable but very optimistic assumptions about the demands of the players who are not included in the coalition. In this paper, in addition to presenting this model and justifying its relevance, we introduce allocation rules and extend the properties of efficiency, additivity, symmetry, and null player property to this setting. We demonstrate that these four properties are insufficient to find a unique allocation rule and define three properties involving null players and nullifying players that allow the identification of unique allocation rules. The allocation rules we identify are the Midpoint Shapley Value and the Equal Division RuleThey also acknowledge the financial support of the University of Santiago de Compostela, of Ministerio de Ciencia e Innovación through Projects ECO2008-03484-C02-02 and MTM2011-27731-C03, and of Xunta de Galicia through Project INCITE09-207-064-PRS