An experimental investigation of fairness and reciprocal behavior in a triangular principal-multiagent relationship

Issues of fairness in hierarchies have been mostly investigated - both theoretically and experimentally - within dyadic principle-agent relationships. In this paper we consider triangular principal-multiagents structures, integrating vertical hierarchical relationships with horizontal agent-to-agent ones. We explore in the laboratory a game that allows to investigate how principal's fairness affects cooperation between two interdependent agents performing a simple production task. Our experimental findings show that perceived fairness of principal's actions may trigger reciprocation in agent's behavior, affecting how agents play the production game

q \bar q-potential

We show how to define and compute in a non-perturbative way the potential between q and \bar q colour sources in the singlet and octet (adjoint) representation of the colour group.Comment: 25 pages, REVTeX

An Experimental Investigation of Fairness and Reciprocal Behavior in a Triangular Principal'-Multiagent Relationship.

A laboratory investigation of a simple agency model that allow to study how the principal's fairness affects the attitude towards cooperation between two interdependent agents performing a simple production task.principal-agent theory; prisoner's dilemma; reciprocity; fairness; experimental economics

Mean-Field Sparse Optimal Control

We introduce the rigorous limit process connecting finite dimensional sparse optimal control problems with ODE constraints, modeling parsimonious interventions on the dynamics of a moving population divided into leaders and followers, to an infinite dimensional optimal control problem with a constraint given by a system of ODE for the leaders coupled with a PDE of Vlasov-type, governing the dynamics of the probability distribution of the followers. In the classical mean-field theory one studies the behavior of a large number of small individuals freely interacting with each other, by simplifying the effect of all the other individuals on any given individual by a single averaged effect. In this paper we address instead the situation where the leaders are actually influenced also by an external policy maker, and we propagate its effect for the number $N$ of followers going to infinity. The technical derivation of the sparse mean-field optimal control is realized by the simultaneous development of the mean-field limit of the equations governing the followers dynamics together with the $\Gamma$-limit of the finite dimensional sparse optimal control problems.Comment: arXiv admin note: text overlap with arXiv:1306.591

On the evaluation of the improvement parameter in the lattice Hamiltonian approach to critical phenomena

In lattice Hamiltonian systems with a quartic coupling $\gamma$, a critical value $\gamma^*$ may exist such that, when $\gamma=\gamma^*$, the leading irrelevant operator decouples from the Hamiltonian and the leading nonscaling contribution to renormalization-group invariant physical quantities (evaluated in the critical region) vanishes. The 1/N expansion technique is applied to the evaluation of $\gamma^*$ for the lattice Hamiltonian of vector spin models with O(N) symmetry. As a byproduct, systematic asymptotic expansions for the relevant lattice massive one-loop integrals are obtained.Comment: Conclusions clarified; 26 pages, 6 figures, RevTeX

Copyright vs. Copyleft Licencing and Software Development

This article aims at clarifying the role played by licenses within the increasingly relevant Open Source Software (OSS) phenomenon. In particular, the article explores from a theoretical point of view the comparative properties of the two main categories of OSS license--copyleft and non-copyleft licenses--in terms of their ability to stimulate innovation and coordination of development efforts. In order to do so, the paper relies on an incomplete contracting model. The model shows that, in spite of the fact that copyleft licenses entail the enjoyment of a narrower set of rights by both licensors and licensees, they may be preferred to non-copyleft licenses when coordination of complementary investments in development is important. It thus provides a non-ideologically-based explanation for the puzzling evidence showing the dominance, in terms of diffusion, of copyleft licenses.intellectual property rights, open source, copyright, copyleft, GPL license, incentives to innovation.

Asymptotic scaling from strong coupling in 2-d lattice chiral models

Two dimensional $N=\infty$ lattice chiral models are investigate by a strong coupling analysis. Strong coupling expansion turns out to be predictive for the evaluation of continuum physical quantities, to the point of showing asymptotic scaling (within 5\%).Comment: 3 pages, PostScript file, contribution to conference LATTICE '9

Mean-Field Pontryagin Maximum Principle

International audienceWe derive a Maximum Principle for optimal control problems with constraints given by the coupling of a system of ordinary differential equations and a partial differential equation of Vlasov-type with smooth interaction kernel. Such problems arise naturally as Gamma-limits of optimal control problems constrained by ordinary differential equations, modeling, for instance, external interventions on crowd dynamics by means of leaders. We obtain these first-order optimality conditions in the form of Hamiltonian flows in the Wasserstein space of probability measures with forward-backward boundary conditions with respect to the first and second marginals, respectively. In particular, we recover the equations and their solutions by means of a constructive procedure, which can be seen as the mean-field limit of the Pontryagin Maximum Principle applied to the optimal control problem for the discretized density, under a suitable scaling of the adjoint variables

The critical equation of state of three-dimensional XY systems

We address the problem of determining the critical equation of state of three-dimensional XY systems. For this purpose we first consider the small-field expansion of the effective potential (Helmholtz free energy) in the high-temperature phase. We compute the first few nontrivial zero-momentum n-point renormalized couplings, which parametrize such expansion, by analyzing the high-temperature expansion of an improved lattice Hamiltonian with suppressed leading scaling corrections. These results are then used to construct parametric representations of the critical equation of state which are valid in the whole critical regime, satisfy the correct analytic properties (Griffith's analyticity), and take into account the Goldstone singularities at the coexistence curve. A systematic approximation scheme is introduced, which is limited essentially by the number of known terms in the small-field expansion of the effective potential. From our approximate representations of the equation of state, we derive estimates of universal ratios of amplitudes. For the specific-heat amplitude ratio we obtain A^+/A^-=1.055(3), to be compared with the best experimental estimate A^+/A^-=1.054(1).Comment: 23 pages, 2 figures, RevTe