Mergeable weighted majority games and characterizations of some power indices

In this paper, we introduce a notion of mergeable weighted majority games with the aim of providing the first characterization of the Colomer–Martínez power index (Colomer and Martínez in J Theor Polit 7(1):41–63, 1995). Furthermore, we define and characterize a new power index for the family of weighted majority games that combines ideas of the Public Good (Holler in Polit Stud 30(2):262–271, 1982) and Colomer–Martínez power indices. Finally, we analyze the National Assembly of Ecuador using these and some other well-known power indicesWe would like to thank Balbina V. Casas-Méndez and two anonymous referees for their valuable comments. This work is part of the R+D+I project grants MTM2017-87197-C3-2-P, MTM2017-87197-C3-3-P, PID2021-124030NB-C32, and PID2021-124030NB-C33, that were funded by MCIN/AEI/10.13039/501100011033/ and by “ERDF A way of making Europe”/EU. This research was also funded by Grupos de Referencia Competitiva ED431C-2020/03 and ED431C-2021/24 from the Consellería de Cultura, Educación e Universidades, Xunta de Galicia. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer NatureS

On horizontal cooperation in linear production processes with a supplier that controls a limited resource

In this paper we consider a two-echelon supply chain with one supplier that controls a limited resource and a finite set of manufacturers who need to purchase this resource. We analyze the effect of the limited resource on the horizontal cooperation of manufacturers. To this end, we use cooperative game theory and the existence of stable distributions of the total profit among the manufacturers as a measure of the possibilities of cooperation. The game theoretical model that describes the horizontal cooperation involves externalities, which arise because of the possible scarcity of the limited resource and the possible coalition structures that can be formed. Furthermore, manufacturers do not know how the supplier will allocate the limited resource, therefore, how much of this resource they will obtain is uncertain for all concerned. Nevertheless, when the limited resource is not scarce for the grand coalition, the existence of stable distributions of the total profit is guaranteed and consequently the collaboration among the manufacturers is profitable for them all. In the event that the limited resource is insufficient for the grand coalition, we introduce a new cooperative game that assesses the expectations of each coalition of manufacturers regarding the amount of the limited resource they can obtain. We analyze two extreme expectations: the optimistic and the pessimistic. In the optimistic case, we cannot reach a conclusion regarding the full cooperation of the manufacturers. In the pessimistic case, with one reasonable assumption, the existence of stable distributions of the total profit is guaranteed and as a result the collaboration among manufacturers is a win–win deal.Ministerio de Economía y Competitividad | Ref. MTM2014-54199-PMinisterio de Economía y Competitividad | Ref. MTM2014-53395-C3-3-PFundación Séneca | Ref. 19320/PI/1

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

Análise e modelaxe de opinión sobre o sector enoturístico da provincia de Ourense

O obxectivo principal deste traballo é analizar as opinións realizadas na plataforma Google Maps sobre un conxunto de adegas da provincia de Ourense. Para iso utilizaranse distintas ferramentas estatísticas que nos servirán para facer desde un estudo descritivo básico ata un estudo e unha análise do contidos dos comentarios publicados nesta plataforma. Un primeiro modelo formulado explica a valoración numérica da adega en función da lonxitude do comentario, da súa polaridade e da interacción entrambas. Tamén ao analizar o contido semántico dos comentarios se poden atopar catro grandes grupos de temas tratados: o viño, o trato recibido, aspectos da experiencia ou da visita e outro grupo de aspectos diferentes aos anteriores

Análise estatística do mercado de aloxamento turístico da provincia de Ourense dende unha nova perspectiva: a análise de datos composicionais

O obxectivo principal deste traballo é analizar os datos recollidos na enquisa sobre a utilización das vivendas do uso turístico na provincia de Ourense dende o punto de vista composicional. Despois dun proceso de familiarización cos datos de natureza composicional, realizouse unha análise descritiva das variables que indicaban a repartición do gasto dos e das turistas que tiñan esta estrutura composicional. Na segunda etapa aplicouse un modelo de regresión loxística coa covarianza composicional. Finalmente, recolléronse os datos procedentes de fontes secundarias do Instituto Galego de Estatística para realizar unha análise da evolución temporal dunha serie composicional que representaba o número de persoas viaxeiras mensuais na provincia de Ourense. Os resultados obtidos indican que é recomendable ter en conta este tipo de estrutura de datos para acadar información sobre a repartición ou a interacción entre as posibles partes

Valle de las Orquídeas: un yacimiento al aire libre del Pleistoceno Superior en la Sierra de Atapuerca (Burgos)

The site of Valle de las Orquídeas is the first Upper Pleistocene open-air locality excavated at Sierra de Atapuerca We have two TL dates from the terra-rossa forming the stratigraphic sequences: 27,507 ± 2,295 years BP and 29,955 ± 2,319 years BP. The archaeological record includes 306 artefacts. This assemblage is technologically homogeneous, reflecting a Middle Palaeolithic technical background, associated with some Upper Palaeolithic features. However, retouching techniques are unusual, since they move further away from that often used during both technological periods.El yacimiento del Valle de las Orquídeas constituye el primer lugar de ocupación al aire libre del Pleistoceno superior, localizado y excavado en la Sierra de Atapuerca. Contamos con dos dataciones de TL en la terra-rossa que forma la base de las secuencias estratigráficas estudiadas, las cuales arrojan una edad de 27.507 ± 2.295 años BP y 29.955 ± 2.319 años BP. El registro arqueológico se restringe a un conjunto lítico formado por 306 piezas. Este conjunto industrial es tecnológicamente homogéneo y se caracteriza por reflejar un substrato técnico típico del Paleolítico Medio, unido a ciertos rasgos del Paleolítico Superior. No obstante, es llamativa la configuración de útiles, que se aleja de las técnicas comúnmente utilizadas en ambos periodos