Enemies and Friends in Hedonic Games: Individual Deviations, Stability and Manipulation

We consider hedonic games with separable preferences, and explore the existence of stable coalition structures if only individual deviations are allowed.For two natural subdomains of separable preferences, namely preference domains based on (1) aversion to enemies and (2) appreciation of friends, we show that an individually stable coalition structure always exist, and a Nash stable coalition structure exists when mutuality is imposed.Moreover, we show that on the domain of separable preferences a contractual individually stable coalition structure can be obtained in polynomial time.Finally, we prove that, on each of the two subdomains, the corresponding algorithm that we use for finding Nash stable and individually stable coalition structures turns out to be strategy-proof.additive separability;coalition formation;hedonic games;stability;strategy-proofness

On the Axiomatic Characterization of "Who is a J?"

Recent work by Kasher and Rubinstein (1997) considers the problem of group identification from a social choice perspective.These authors provide an axiomatic characterization of a liberal aggregator whereby the group consist of those and only those individuals each of which views oneself a member of the group.In the present paper we show that the five axioms used in Kasher and Rubinstein s characterization of the liberal aggregator are not independent and prove that only three of their original axioms are necessary and sufficient for the required characterization.aggregation;group identification;axiomatic method

Procedural Group Identification

In this paper we axiomatically characterize two recursive procedures for defining a social group.The first procedure starts with the set of all individuals who define themselves as members of the social group, while the starting point of the second procedure is the set of all individuals who are defined by everyone in the society as group members.Both procedures expand these initial sets by adding individuals who are considered to be appropriate group members by someone in the corresponding initial set, and continue inductively until there is no possibility of expansion any more.identification;social groups;social identity

Simple Priorities and Core Stability in Hedonic Games

In this paper we study hedonic games where each player views every other player either as a friend or as an enemy.Two simple priority criteria for comparison of coalitions are suggested, and the corresponding preference restrictions based on appreciation of friends and aversion to enemies are considered.It turns out that the first domain restriction guarantees non-emptiness of the strong core and the second domain restriction ensures non-emptiness of the weak core of the corresponding hedonic games.Moreover, an element of the strong core under friends appreciation can be found in polynomial time, while finding an element of the weak core under enemies aversion is NP-hard.We examine also the relationship between our domain restrictions and some su.cient conditions for non-emptiness of the core already known in the literature.core;stability;games

The Ecological Meaning of the Presence of God in Elizabeth Ann Seton’s Reflections and Translations Based on Elizabeth Bayley Seton: Collected Writings Volumes 3a & 3b

In her third interpretation of Elizabeth Seton’s spirituality within the framework of ecological theology, Sun Hae Kim examines volumes 3a and 3b of Elizabeth’s writings. These volumes cover Elizabeth’s entire life. The presence of God was “the mystery that not only sustained her throughout her life but also united her vision of the entire universe of natural creation and humanity into one.” Kim also puts Elizabeth’s views of creation, humanity, suffering, and death within the context of three ecological theologians: Hildegard of Bingen, Sallie McFague, and Elizabeth A. Johnson. According to Elizabeth, God’s presence “consecrates every part of the universe”; caring for the earth—which is God’s body according to Johnson—is, as Kim says, “an act of obedience to the Creator, who wants all life to flourish.” At the end of time, Elizabeth looked to “the complete transformation of the earth,” which for her involved our salvation and “the glory of the natural world.” Death and suffering, as a part of the natural world, are a part of ecology in which God is present as well. Moreover, “suffering is a mystery that humbles and unites both humans and non-human living beings of the earth.

The Ecological Spirituality of Elizabeth Ann Seton

Some ecologists believe that the global environmental crisis has been caused by placing humanity at the top of the ecosystem. They have asked religious traditions to help develop new ethics that restore equilibrium to the relationship between humanity and nature. One way to do this is to examine traditional texts from an ecological perspective. With extensive quotations, Sung-Hae Kim demonstrates how Elizabeth Seton saw the link between humanity and nature and how she experienced God in nature. Kim writes that Elizabeth learned to see suffering and death as transformative and part of an “ecological balance,” which led to trust in God. According to Kim, “while recognizing the rhythm of time in nature, Elizabeth realized the importance of living in the present and learned to be content in all situations by acquiring the virtues of moderation and harmony.” Her spirituality is considered within the context of ideas from four philosophers of ecology, Arne Naess, Aldo Leopold, Murray Bookchin, and Anthony Weston

On the Axiomatic Characterization of "Who is a J?"

Recent work by Kasher and Rubinstein (1997) considers the problem of group identification from a social choice perspective.These authors provide an axiomatic characterization of a liberal aggregator whereby the group consist of those and only those individuals each of which views oneself a member of the group.In the present paper we show that the five axioms used in Kasher and Rubinstein s characterization of the liberal aggregator are not independent and prove that only three of their original axioms are necessary and sufficient for the required characterization

Indifference as the Freedom of the Heart: The Spiritual Fruit of Apostolic Mysticism—Christian, Confucian, and Daoist Cases

Sung-Hae Kim asserts that mysticism can lead to action rather than just contemplation. For her, apostolic mysticism leads to “freedom of the heart,” which is “‘indifference’ in Christianity, ‘absence of private mind’ in Confucianism, and ‘equitable and constant ordinary mind’ in Daoism.” Practitioners of this virtue representing these three traditions respectively are Vincent de Paul, Cheng Yi, and Yin Zhiping. For Vincent, indifference was the total freedom from desires and attachments that enabled one to follow God’s will in all things. Vincent primarily characterized indifference as obedience, a willingness to be sent anywhere and to undertake any work to serve God. For Cheng Yi, absence of private mind meant an absence of individual selfish desires. The virtue of benevolence, obtained through sharing with others and listening to them, would overcome the private mind in favor of the public mind or greater good, which is the principle of Heaven. In absence of private mind, one would naturally recognize and carry out the good without making it an act of self-will. For Yin Zhiping, the constant ordinary mind meant facing all situations with moderation. Kim explains how the ordinary mind “integrates contemplation and action into one.

Elizabeth Ann Seton’s Vision of Ecological Community. Based on Elizabeth Bayley Seton: Collected Writings, Volume Two

This article is a companion to “The Ecological Spirituality of Elizabeth Ann Seton,” which appeared in Vincentian Heritage 32:2 (2015). Using extensive quotations from Elizabeth’s letters, Sung-Hae Kim explores how she practiced ecological principles in her relationships with family, friends, and members of her religious community. Elizabeth’s relationships with her students, parents of students, other benefactors, and church leaders are also discussed. Ecological principles include mutual aid, self-governance, harmony, and balance. Elizabeth used these and others to form interconnected ecological communities. The concept of ecological community is defined, drawing from the work of the philosophers Peter Kropotkin, Henry David Thoreau, and Murray Bookchin. Ecological aspects of the Sisters of Charity’s ministry and of the community’s structure and governance are described