Search results for " Reciprocity."

Athènes et les « Philaïdes » Formes de réciprocité entre les aristocrates et la polis

2009

This article aims at exploring the relationship between Athens and the members of the Miltiades and Cimon family, the so-called Philaids. The history of this lineage significantly marked the development of Athens in the archaic period. In spite of the contradictory traditions regarding these historical figures, a lexical analysis of the sources allows an interpretation of their relationship with the polis in terms of reciprocity. I will argue that this is a special form of reciprocity, generated by the unequal and asymmetric relationship that this family seems to have had with Athens.

Parabolic Subgroups of Artin Groups

1997

Abstract Let ( A , Σ) be an Artin system. For X  ⊆ Σ, we denote by A X the subgroup of A generated by X . Such a group is called a parabolic subgroup of A . We reprove Van der Lek's theorem: “a parabolic subgroup of an Artin group is an Artin group.” We give an algorithm which decides whether two parabolic subgroups of an Artin group are conjugate. Let A be a finite type Artin group, and let A X be a parabolic subgroup with connected associated Coxeter graph. The quasi-centralizer of A X in A is the set of β in A such that β X β −1  =  X . We prove that the commensurator of A X in A is equal to the normalizer of A X in A , and that this group is generated by A X and the quasi-centralizer of…

SURFACE SUBGROUPS OF RIGHT-ANGLED ARTIN GROUPS

2007

We consider the question of which right-angled Artin groups contain closed hyperbolic surface subgroups. It is known that a right-angled Artin group $A(K)$ has such a subgroup if its defining graph $K$ contains an $n$-hole (i.e. an induced cycle of length $n$) with $n\geq 5$. We construct another eight "forbidden" graphs and show that every graph $K$ on $\le 8$ vertices either contains one of our examples, or contains a hole of length $\ge 5$, or has the property that $A(K)$ does not contain hyperbolic closed surface subgroups. We also provide several sufficient conditions for a \RAAG to contain no hyperbolic surface subgroups. We prove that for one of these "forbidden" subgraphs $P_2(6)$, …

Reciprocity, matching and conditional cooperation in two public goods games

2005

Previous experimental and empirical evidence has identified social preferences in the voluntary provision of public goods. A number of competing models of such preferences have been proposed. We provide evidence for one model of behavior in these games, reciprocity (or matching, or conditional cooperation). Consistent with previous research, we find that participants in the voluntary contribution mechanism attempt to match the contributions of others in their group. We also examine participants in a related game with different equilibria, the weakest-link mechanism. Here, in contrast, participants contribute so as to match the minimum contribution of others in their group.

Non-Equilibrium Thermodinamic analysis of rotating counterflow superfluid turbulence

2008

Two alternative evolution equations for the vortex line density L in counterflow superfluid turbulence in 4He were proposed by Vinen in 1958. These equations was recently generalized to counterflow superfluid turbulence in rotating containers. Here, according with the formalism of Non-Equilibrium Thermodynamics, the compatibility between the alternative Vinen equation as evolution equation for the vortex line density in rotating counterflow turbulence and the velocity of the superfluid component is studied. From the compatibility request a new term dependent on the anisotropy of the tangle arises.

Affrontare il cyberbullismo in classe. Comprendere e riconoscere gli effetti collaterali dei social network

2018

Il cyberbullismo rappresenta un fenomeno complesso che si manifesta con modalità articolate. Le difficoltà più evidenti sono: la possibilità, da parte dell'aggressore di rimanere anonimo; la numerosità degli spettatori; l'assenza di supervisione da parte degli adulti; il distacco tra gesto e significato attribuito. Tale fenomeno implica la necessità di promuovere un'educazione digitale e affettivo-relazionale attraverso attività educative capaci di prevenire i numerosi e complessi pericoli della rete. Fondamentale, ancora, risulta educare al rispetto della reciprocità, delle norme sociali, dell'intenzionalità del Noi, così da favorire un sano sviluppo psicosociale della persona inserita - o…

Beneficium e iniuria. Rappresentazioni del dono e dell’offesa nel De beneficiis di Seneca

2018

Non-equilibrium thermodynamics analysis of rotating counterflow superfluid turbulence

2010

In two previous papers two evolution equations for the vortex line density $L$, proposed by Vinen, were generalized to rotating superfluid turbulence and compared with each other. Here, the already generalized alternative Vinen equation is extended to the case in which counterflow and rotation are not collinear. Then, the obtained equation is considered from the viewpoint of non-equilibrium thermodynamics. According with this formalism, the compatibility between this evolution equation for $L$ and that one for the velocity of the superfluid component is studied. The compatibility condition requires the presence of a new term dependent on the anisotropy of the tangle, which indicates how the…

Contentio honestissima e certamen nequitiae nelle opere di Seneca

2017

Nel De beneficiis (I 4.3-4; III 21-22; V. 1-5), Seneca si serve del motivo della contentio per rappresentare il meccanismo virtuoso che suggerisce di impiegare nella prassi dei benefici, in cui la sconfitta non è mai considerata vergognosa. Come mostrano i più recenti studi sul trattato (in particolare, i contributi a cura di G. Picone, R. R. Marchese e R. Raccanelli), questo modulo non vanifica le diseguaglianze sociali delle relazioni asimmetriche, ma offre un modello di comportamento positivo consistente in una forma di alternanza virtuosa. Così, alla luce degli studi antropologici sul dono e sulla reciprocità nella società romana, il contributo si propone di mettere a confronto la dinam…

The interplay of reciprocity propensity and inequality aversion in two-person games

2020

Economic normative models assume that economic actors are fully rational and selfish while recent studies acknowledge the emotional influence of an economic decision and call for further investigation of biases in decision making. Most decisions involve multiple actors who make decisions following a sequential path as reflected by decision trees; this contingency makes a call for the game theory contribution in the economic decision field. Two-person games are widely used to represent a typical framework of economic decisions. This study aims at further investigating psychological biases affecting decisions in a two-person sequential game. So far similar studies have focused on the principa…