scholarly journals Unknown Agents in Friends Oriented Hedonic Games: Stability and Complexity

2019 ◽  
Vol 33 ◽  
pp. 1756-1763 ◽  
Author(s):  
Nathanaël Barrot ◽  
Kazunori Ota ◽  
Yuko Sakurai ◽  
Makoto Yokoo
Keyword(s):  
Negative Impact ◽  
Coalition Structure ◽  
The Core ◽  
Stable Coalition ◽  
Hedonic Games ◽  
Np Complete

We study hedonic games under friends appreciation, where each agent considers other agents friends, enemies, or unknown agents. Although existing work assumed that unknown agents have no impact on an agent’s preference, it may be that her preference depends on the number of unknown agents in her coalition. We extend the existing preference, friends appreciation, by proposing two alternative attitudes toward unknown agents, extraversion and introversion, depending on whether unknown agents have a slightly positive or negative impact on preference. When each agent prefers coalitions with more unknown agents, we show that both core stable outcomes and individually stable outcomes may not exist. We also prove that deciding the existence of the core and the existence of an individual stable coalition structure are respectively NPNP-complete and NP-complete.

scholarly journals Core Stability in Hedonic Games among Friends and Enemies: Impact of Neutrals

2017 ◽  
Author(s):  
Kazunori Ohta ◽  
Nathanaël Barrot ◽  
Anisse Ismaili ◽  
Yuko Sakurai ◽  
Makoto Yokoo
Keyword(s):  
Polynomial Time ◽  
Coalition Structure ◽  
Core Stability ◽  
The Core ◽  
Stable Coalition ◽  
Hedonic Games ◽  
Np Complete ◽  
Strict Core

We investigate hedonic games under enemies aversion and friends appreciation, where every agent considers other agents as either a friend or an enemy. We extend these simple preferences by allowing each agent to also consider other agents to be neutral. Neutrals have no impact on her preference, as in a graphical hedonic game.Surprisingly, we discover that neutral agents do not simplify matters, but cause complexity. We prove that the core can be empty under enemies aversion and the strict core can be empty under friends appreciation. Furthermore, we show that under both preferences, deciding whether the strict core is non-empty, is NP^NP-complete. This complexity extends to the core under enemies aversion. We also show that under friends appreciation, we can always find a core stable coalition structure in polynomial time.

scholarly journals Testing stability properties in graphical hedonic games

2021 ◽  
Vol 35 (2) ◽  
Author(s):  
Hendrik Fichtenberger ◽  
Anja Rey
Keyword(s):  
Time Complexity ◽  
Coalition Structure ◽  
Property Testing ◽  
Core Stability ◽  
Bounded Degree ◽  
Coalition Structures ◽  
Input Size ◽  
Stable Coalition ◽  
Hedonic Games ◽  
The Stability

AbstractIn hedonic games, players form coalitions based on individual preferences over the group of players they could belong to. Several concepts to describe the stability of coalition structures in a game have been proposed and analysed in the literature. However, prior research focuses on algorithms with time complexity that is at least linear in the input size. In the light of very large games that arise from, e.g., social networks and advertising, we initiate the study of sublinear time property testing algorithms for existence and verification problems under several notions of coalition stability in a model of hedonic games represented by graphs with bounded degree. In graph property testing, one shall decide whether a given input has a property (e.g., a game admits a stable coalition structure) or is far from it, i.e., one has to modify at least an $$\epsilon$$ ϵ -fraction of the input (e.g., the game’s preferences) to make it have the property. In particular, we consider verification of perfection, individual rationality, Nash stability, (contractual) individual stability, and core stability. While there is always a Nash-stable coalition structure (which also implies individually stable coalitions), we show that the existence of a perfect coalition structure is not tautological but can be tested. All our testers have one-sided error and time complexity that is independent of the input size.

scholarly journals Pendidikan Karakter Berbasis Local Wisdom (studi kasus di TK Islam PAS Munqidzatun Nasyi’ah Desa Wilangan Kecamatan Sambit Kabupaten Ponorogo)

2019 ◽  
Vol 14 (01) ◽  
pp. 49-62
Author(s):  
Tamrin Fatoni
Keyword(s):  
Character Education ◽  
Negative Impact ◽  
Field Research ◽  
Descriptive Study ◽  
Qualitative Approach ◽  
Data Display ◽  
Free Communication ◽  
The Core ◽  
Data Collection Technique

Developing powerful communications technology has created unlimited free communication. The negative impact of this phenomenon is when a culture that is not good from the outside is swallowed out by children who are still young. As a result, it will easily experience cultural dislocation. One of the legacies of local wisdom that are not interested in the midst of the community is the Javanese dolanan song. Therefore all efforts must be sought from the very beginning. These efforts can be done through various ways, including habituation of children to play and sing songs (songs) dolanan Javanese, which actually contains a lot of character values. This study included a descriptive study, a case study at PAS Munqidzatun Nasyi'ah Wilangan Islamic Kindergarten. This study aims to describe; 1. Describe the form of character education in PAS Munqidzatun Nasyi'ah Wilangan Islamic Kindergarten. 2. Describe the strategy for implementing character education in PAS Munqidzatun Nasyi'ah Wilangan Islamic Kindergarten. 3. Describe the results of character education in PAS Munqidzatun Nasyi'ah Wilangan Islamic Kindergarten. This research includes field research using a qualitative approach. In collecting data, the author uses the method of interviews, observation, and documentation as a data collection technique. The technique chosen in data analysis is data reduction, data display and conclusions or verification. From this study it can be seen that: 1. the form of character education in PAS Islamic Kindergarten Munqidzatun Nasyi'ah Wilangan is a local widom-based character education (local wisdom) in the form of Javanese dolanan songs. There are three dolanan songs used for character planting, namely Sluku-sluku Bathok, gundul-gundul Pachol and Menthok-menthok. 2. The strategy for the implementation of character education in PAS Islamic Kindergarten Munqidzatun Nasyi'ah Wilangan is to use reflective methods. This can be proven by giving an explanation of moral values ​​to students, after the song is finished the song is sung both in class before the core lesson begins or while playing outside the classroom. 3. The results of character education at PAS Islam Munqidzatun Nasyi'ah Wilangan Kindergarten have fulfilled the values ​​of the basic characters, namely: a. Respectful and polite character through greeting each other and shaking hands. b. This character of independence and responsibility can be seen from throwing garbage in its place.

FA and Motivating Reasons

2021 ◽  
pp. 153-165
Author(s):  
Toni Rønnow-Rasmussen
Keyword(s):  
Negative Impact ◽  
Guise Of The Good ◽  
The Core ◽  
Motivating Reasons ◽  
Core Elements ◽  
Core Part

The main aim in ‘FA and Motivating Reasons’ is to clear the ground for the discussion in Chapter 11 by drawing attention to some notions and distinctions that help us to understand the core elements of fitting-attitude analysis (FA). In particular, the distinction between explanatory and motivating reason plays a core part in this and the next chapter. In light of this distinction, the focus is on whether we should accept either ‘the guise of the good thesis’ or the more plausible ‘guise of reason thesis’. Eventually (in Chapter 11), it is argued that we should endorse neither of these. While the previous chapters gave us a positive insight (they lead to a modification of the FA pattern of analysis), this—and the next chapter also, as we shall see—will mainly have a negative impact. It suggests we should refrain from introducing certain modifications of FA analysis that at first sight might seem compelling.

scholarly journals Size Monotonicity and Stability of the Core in Hedonic Games

2011 ◽  
Author(s):  
Dinko Dimitrov ◽  
Shao-Chin Sung
Keyword(s):  
The Core ◽  
Hedonic Games

scholarly journals Stable and Envy-free Partitions in Hedonic Games

2019 ◽  
Author(s):  
Nathanaël Barrot ◽  
Makoto Yokoo
Keyword(s):  
Coalition Formation ◽  
Grand Coalition ◽  
Core Stability ◽  
Pareto Optimal ◽  
Hedonic Games ◽  
Np Complete ◽  
Stability Notions

In this paper, we study coalition formation in hedonic games through the fairness criterion of envy-freeness. Since the grand coalition is always envy-free, we focus on the conjunction of envy-freeness with stability notions. We first show that, in symmetric and additively separable hedonic games, an individually stable and justified envy-free partition may not exist and deciding its existence is NP-complete. Then, we prove that the top responsiveness property guarantees the existence of a Pareto optimal, individually stable, and envy-free partition, but it is not sufficient for the conjunction of core stability and envy-freeness. Finally, under bottom responsiveness, we show that deciding the existence of an individually stable and envy-free partition is NP-complete, but a Pareto optimal and justified envy-free partition always exists.

scholarly journals Cooperative Games with Overlapping Coalitions

2010 ◽  
Vol 39 ◽  
pp. 179-216 ◽  
Author(s):  
G. Chalkiadakis ◽  
E. Elkind ◽  
E. Markakis ◽  
M. Polukarov ◽  
N. R. Jennings
Keyword(s):  
Coalition Formation ◽  
Cooperative Games ◽  
Cooperative Game Theory ◽  
Coalition Structure ◽  
Coalitional Games ◽  
The Core ◽  
Coalition Structures ◽  
Coalition Formation Process ◽  
The Social ◽  
Overlapping Coalitions

In the usual models of cooperative game theory, the outcome of a coalition formation process is either the grand coalition or a coalition structure that consists of disjoint coalitions. However, in many domains where coalitions are associated with tasks, an agent may be involved in executing more than one task, and thus may distribute his resources among several coalitions. To tackle such scenarios, we introduce a model for cooperative games with overlapping coalitions—or overlapping coalition formation (OCF) games. We then explore the issue of stability in this setting. In particular, we introduce a notion of the core, which generalizes the corresponding notion in the traditional (non-overlapping) scenario. Then, under some quite general conditions, we characterize the elements of the core, and show that any element of the core maximizes the social welfare. We also introduce a concept of balancedness for overlapping coalitional games, and use it to characterize coalition structures that can be extended to elements of the core. Finally, we generalize the notion of convexity to our setting, and show that under some natural assumptions convex games have a non-empty core. Moreover, we introduce two alternative notions of stability in OCF that allow a wider range of deviations, and explore the relationships among the corresponding definitions of the core, as well as the classic (non-overlapping) core and the Aubin core. We illustrate the general properties of the three cores, and also study them from a computational perspective, thus obtaining additional insights into their fundamental structure.

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