3,758 research outputs found
Convexity in stochastic cooperative situations
This paper introduces a new model concerning cooperative situations in which the payoffs are modeled by random variables. We analyze these situations by means of cooperative games with random payoffs. Special attention is paid to three types of convexity, namely coalitional-merge, individual-merge and marginal convexity. The relations between these types are studied and in particular, as opposed to their deterministic counterparts for TU games, we show that these three types of convexity are not equivalent. However, all types imply that the core of the game is nonempty. Sufficient conditions on the preferences are derived such that the Shapley value, defined as the average of the marginal vectors, is an element of the core of a convex game
Convexity in Stochastic Cooperative Situations
AMS classification: 90D12.
On the Convexity of News Vendor Games
This study considers a simple newsvendor situation that consists of n retailers, all selling the same item with common purchasing costs and common selling prices.Groups of retailers might increase their expected joint profit by inventory centralization, which means that they make a joint order to satisfy total future demand.The resulting newsvendor games are shown to have non-empty cores in the literature.This study investigates convexity of newsvendor games.We focus our analysis on the class of newsvendor games with independent symmetric unimodal demand distributions after providing several examples outside this class that are not convex.Several interesting subclasses, containing convex games only, are identified.Additionally, we illustrate that these results can not be extended to all games in this class.game theory;inventory centralization;newsvendor;convexity
Transferable Utility Games with Uncertainty
We introduce the concept of a TUU-game, a transferable utility game with uncertainty. In a TUU-game there is uncertainty regarding the payoffs of coalitions. One out of a finite number of states of nature materializes and conditional on the state, the players are involved in a particular transferable utility game. We consider the case without ex ante commitment possibilities and propose the Weak Sequential Core as a solution concept. We characterize the Weak Sequential Core and show that it is non-empty if all ex post TUgames are convex
On Convexity for NTU-Games
For cooperative games with transferable utility, convexity has turned out to be an important and widely applicable concept.Convexity can be defined in a number of ways, each having its own specific attractions.Basically, these definitions fall into two categories, namely those based on a supermodular interpretation and those based on a marginalistic interpretation.For games with non-transferable utility, however, the literature only offers two kinds of convexity, ordinal and cardinal convexity, which both extend the supermodular interpretation.In this paper, we introduce and analyse three new types of convexity for NTU-games that generalise the marginalistic interpretation of convexity.game theory
Supply chain collaboration
In the past, research in operations management focused on single-firm analysis. Its goal was to provide managers in practice with suitable tools to improve the performance of their firm by calculating optimal inventory quantities, among others. Nowadays, business decisions are dominated by the globalization of markets and increased competition among firms. Further, more and more products reach the customer through supply chains that are composed of independent firms. Following these trends, research in operations management has shifted its focus from single-firm analysis to multi-firm analysis, in particular to improving the efficiency and performance of supply chains under decentralized control. The main characteristics of such chains are that the firms in the chain are independent actors who try to optimize their individual objectives, and that the decisions taken by a firm do also affect the performance of the other parties in the supply chain. These interactions among firmsâ decisions ask for alignment and coordination of actions. Therefore, game theory, the study of situations of cooperation or conflict among heterogenous actors, is very well suited to deal with these interactions. This has been recognized by researchers in the field, since there are an ever increasing number of papers that applies tools, methods and models from game theory to supply chain problems
Monotonicity Problems of Interval Solutions and the Dutta-Ray Solution for Convex Interval Games
This paper examines several monotonicity properties of value-type interval solutions on the class of convex interval games and focuses on the Dutta-Ray (DR) solution for such games. Well known properties for the classical DR solution are extended to the interval setting. In particular, it is proved that the interval DR solution of a convex interval game belongs to the interval core of that game and Lorenz dominates each other interval core element. Consistency properties of the interval DR solution in the sense of Davis-Maschler and of Hart-Mas-Colell are verified. An axiomatic characterization of the interval DR solution on the class of convex interval games with the help of bilateral Hart-Mas-Colell consistency and the constrained egalitarianism for two-person interval games is given.cooperative interval games;convex games;the constrained egalitarian solution;the equal division core;consistency
Robust Dynamic Cooperative Games
Classical cooperative game theory is no longer a suitable tool for those situations where
the values of coalitions are not known with certainty. Recent works address situations
where the values of coalitions are modelled by random variables. In this work we still
consider the values of coalitions as uncertain, but model them as unknown but bounded
disturbances. We do not focus on solving a specific game, but rather consider a family of
games described by a polyhedron: each point in the polyhedron is a vector of coalitionsâ
values and corresponds to a specific game. We consider a dynamic context where while
we know with certainty the average value of each coalition on the long run, at each time
such a value is unknown and fluctuates within the bounded polyhedron. Then, it makes
sense to define ârobustâ allocation rules, i.e., allocation rules that bound, within a pre-
defined threshold, a so-called complaint vector while guaranteeing a certain average (over
time) allocation vector. We also present as motivating example a joint replenishment
application
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