On the Formation of Interaction Networks in Social Coordination Games

There are many situations where two interacting individuals can benefit from coordinating their actions. We examine the endogenous choice of partners in such social coordination games and the implications for resulting play. We model the interaction pattern as a network where individuals periodically have the discretion to add or sever links to other players. A player chooses whether to add or sever a link based on the (prospective) partner's past behavior. With such endogenous interaction patterns we see multiple stochastically stable states of play, including some that involve play of equilibria in the coordination game that are neither efficient nor risk dominant.

Social Games: Matching and the Play of Finitely Repeated Games

We examine a new class of games, which we call social games, where players not only choose strategies but also choose with whom they play. A group of players who are dissatisfied with the play of their current partners can join together and play a new equilibrium. This imposes new refinements on equilibrium play, where play depends on the relative populations of players in different roles, among other things. We also examine finite repetitions of games where players may choose to rematch in any period. Some equilibria of fixed-player repeated games cannot be sustained as equilibria in a repeated social game. Conversely, the set of repeated matching (or social) equilibria also includes some plays that are not part of any subgame perfect equilibrium of the corresponding fixed-player repeated games. We explore existence under different equilibrium definitions, as well as the relationship to renegotiation-proof equilibrium. It is possible for repeated matching equilibria to be completely distinct from renegotiation-proof equilibria, and even to be Pareto inefficient.Social games, Matching, Games, Repeated games, Renegotiation

Social Games: Matching and the Play of Finitely Repeated Games

We examine a new class of games, which we call social games, where players not only choose strategies but also choose with whom they play. A group of players who are dissatisfied with the play of their current partners can join together and play a new equilibrium. This imposes new refinements on equilibrium play, where play depends on the relative populations of players in different roles, among other things. We also examine finite repetitions of games where players may choose to rematch in any period. Some equilibria of fixed-player repeated games cannot be sustained as equilibria in a repeated social game. Conversely, the set of repeated matching (or social) equilibria also includes some plays that are not part of any subgame perfect equilibrium of the corresponding fixed-player repeated games. We explore existence under different equilibrium definitions, as well as the relationship to renegotiation-proof equilibrium. It is possible for repeated matching equilibria to be completely distinct from renegotiation-proof equilibria, and even to be Pareto inefficient.Social Games, Matching, Games, Repeated Games, Renegotiation

A comparative study of the syrphidae (diptera) from different habitats within Bernwood Forest

1. Syrphidae were chosen as indicators of diversity in samples from five Malaise traps chosen to represent the transition from deciduous to coniferous woodland. 20, 234 syrphids of 115 species were captured between 1 April and 30 September 1980 - 1982. 2. Seasonal distribution is bimodal, with abundance peaks in May and late July through August. This contrasts with unimodal distribution in other habitats. Seasonal variation in aphid quality is proposed as the explanation. 3. Hoverfly species show enormous variation in abundance over the years, but, with one exception, the number of individuals and species at each site gives a consistent ranking each year. More species were caught in the first half of the sampling period whereas more individuals were captured in the second half. 4. Variation in species' abundances each year inhibits the identification of indicator species along the coniferization gradient. 5. Species diversity indices are used to estimate site quality and community structure. The former indices give site rankings in agreement with the number of species present and confirm the relative diversities of the two sampling periods. The latter indices demonstrate community changes over the three years, which is ascribed to the fluctuating nature of the species populations involved. 6. Principal components analysis isolates the catches from all sites according to season. High-diversity sites show more seasonal variation than low-diversity ones. 7. 75% of the syrphids captured have aphidophagous larvae but all five trophic categories are represented. Each site has a distinct trophic composition and this apparent trophic stability questions the over-reliance on the species as the fundamental ecological unit. 8. Chaotic phasing of species abundances, mediated through climatic control, is proposed as a non-equilibrium theory of population control which maximizes niche exploitation whilst minimizing intra-guild competition, thus maintaining species diversity

A preliminary report on energetic space radiation and dose rate analysis

Energetic space radiation and dose rate analysi

Charged particle radiation environment for the LST

Preliminary charged particle dose rates are presented for the LST orbit. The trapped proton component appears to dominate the total dose for the expected shielding available. Typical dose rates should range from 400 to 800 millirads/day

On the Formation of Interaction Networks in Social Coordination Games

There are many situations where two interacting individuals can benefit from coordinating their actions. We examine the endogenous choice of partners in such social coordination games and the implications for resulting play. We model the interaction pattern as a network where individuals periodically have the discretion to add or sever links to other players. With such endogenous interaction patterns we see multiple stochastically stable states of play, including some that involve play of equilibria in the coordination game that are neither efficient nor risk dominant. Thus the endogenous network structure not only has implications for the interaction pattern that emerges, but it also has a significant impact on the play in the coordination game relative to what would arise if the same interaction network were exogenous

Social Games: Matching and the Play of Finitely Repeated Games

We examine a new class of games, which we call social games, where players not only choose strategies but also choose with whom they play. A group of players who are dissatisfied with the play of their current partners can join together and play a new equilibrium. This imposes new refinements on equilibrium play, where play depends on the relative populations of players in different roles, among other things. We also examine finite repetitions of games where players may choose to rematch in any period. Some equilibria of fixed-player repeated games cannot be sustained as equilibria in a repeated social game. Conversely, the set of repeated matching (or social) equilibria also includes some plays that are not part of any subgame perfect equilibrium of the corresponding fixed-player repeated games. We explore existence under different equilibrium definitions, as well as the relationship to renegotiation-proof equilibrium. It is possible for repeated matching equilibria to be completely distinct from renegotiationproof equilibria, and even to be Pareto inefficient