Guaranteed Inertia Functions in Dynamical Games.

This paper deals with inertia functions in control theory introduced in Aubin, Bernardo and Saint-Pierre (2004, 2005) and their adaptation to dynamical games. The inertia function associates with any initial state-control pair the smallest of the worst norms over time of the velocities of the controls regulating viable evolutions. For tychastic systems (parameterized systems where the parameters are tyches, disturbances, perturbations, etc.), the palicinesia of a tyche measure the worst norm over time of the velocities of the tyches. The palicinesia function is the largest palicinesia threshold c such that all evolutions with palicinesia smaller than or equal to c are viable. For dynamical games where one parameter is the control and the other one is a tyche (games against nature or robust control), we define the guaranteed inertia function associated with any initial state-control-tyche triple the best of the worst of the norms of the velocities of the controls and of the tyches and study their properties. Viability Characterizations and Hamilton-Jacobi equations of which these inertia and palicinesia functions are solutions are provided.Viability; dynamical games; inertia function; Tychastic systems; palicinesia;

Differential games through viability theory : old and recent results.

This article is devoted to a survey of results for differential games obtained through Viability Theory. We recall the basic theory for differential games (obtained in the 1990s), but we also give an overview of recent advances in the following areas : games with hard constraints, stochastic differential games, and hybrid differential games. We also discuss several applications.Game theory; Differential game; viability algorithm;

Dynamic Management of Portfolios with Transaction Costs under Tychastic Uncertainty.

We use in this chapter the viability/capturability approach for studying the problem of dynamic valuation and management of a portfolio with transaction costs in the framework of tychastic control systems (or dynamical games against nature) instead of stochastic control systems. Indeed, the very definition of the guaranteed valuation set can be formulated directly in terms of guaranteed viable-capture basin of a dynamical game. Hence, we shall “compute” the guaranteed viable-capture basin and find a formula for the valuation function involving an underlying criterion, use the tangential properties of such basins for proving that the valuation function is a solution to Hamilton-Jacobi-Isaacs partial differential equations. We then derive a dynamical feedback providing an adjustment law regulating the evolution of the portfolios obeying viability constraints until it achieves the given objective in finite time. We shall show that the Pujal—Saint-Pierre viability/capturability algorithm applied to this specific case provides both the valuation function and the associated portfolios.dynamic games; dynamic valuation; tychastic control systems; management of portfolio;

Viabilist and Tychastic Approaches to Guaranteed ALM Problem.

This study reconsiders the problem of hedging a liability by a portfolio made of a riskless asset and an underlying (underlying).Asset and Liability Management; Viability theory;

An invariance kernel representation of ISDS Lyapunov functions

We apply set valued analysis techniques in order to characterize the input-to-state dynamical stability (ISDS) property, a variant of the well known input-to-state stability (ISS) property. Using a suitable augmented differential inclusion we are able to characterize the epigraphs of minimal ISDS Lyapunov functions as invariance kernels. This characterization gives new insight into local ISDS properties and provides a basis for a numerical approximation of ISDS and ISS Lyapunov functions via set oriented numerical methods.ou

Forest Conservation and CO2 Emissions : A Viable Approach.

We adopt viability theory to assess the sustainability of the world’s forests while taking into account some of the competing economic, social, and environmental uses of these forests, namely, timber production, poverty alleviation through agriculture, and air quality as well as the negative externalities that these uses create. We provide insights on the different trade-offs faced to achieve sustainability and draw some policy implications as to what is the path leading to sustainability in the long run.Emissions; Forest; Sustainability; Viability theory;

Domaine de victoire et stratégies viables dans le cas d'une correspondance non-convexe : application à l'anthropologie des pêcheurs selon Fredrik Barth

The anthropologist Fredrik Barth analysed the social forms generated among Norvegian fishermen. His view is well rendered by the mathematical tools of viability theory. The largest set of states from which economic survival is still possible is calculated, as well as the right decision to take at each moment, between risk-taking and following the other vessels. Moreover, the technical condition that the image of the correspondence describing the process at work must be compact, isviolated. We deal with this difficulty and we present the algorithm.L'anthropologue Fredrik Barth a analysé l'émergence des formes sociales chez les pêcheurs norvégiens. Sa perspective est bien modélisée par les outils mathématiques de la théorie de la viabilité, grâce auxquels on peut calculer l'ensemble des états à partir desquels la survie du système est encore possible, ainsi que la bonne décision à prendre à chaque instant, entre explorer ou suivre les autres bateaux. En outre, il se trouve que, techniquement, la condition de compacité des images de la correspondance décrivant le processus de décision n'est pas satisfaite pour pouvoir appliquer tel quel le théorème de viabilité. Cette difficulté est levée dans le cadre de ce modèle des pêcheurs, et l'algorithme de calcul est explicité

Domaine de victoire et stratégies viables dans le cas d'une correspondance non-convexe : application à l'anthropologie des pêcheurs selon Fredrik Barth

The anthropologist Fredrik Barth analysed the social forms generated among Norvegian fishermen. His view is well rendered by the mathematical tools of viability theory. The largest set of states from which economic survival is still possible is calculated, as well as the right decision to take at each moment, between risk-taking and following the other vessels. Moreover, the technical condition that the image of the correspondence describing the process at work must be compact, isviolated. We deal with this difficulty and we present the algorithm.L'anthropologue Fredrik Barth a analysé l'émergence des formes sociales chez les pêcheurs norvégiens. Sa perspective est bien modélisée par les outils mathématiques de la théorie de la viabilité, grâce auxquels on peut calculer l'ensemble des états à partir desquels la survie du système est encore possible, ainsi que la bonne décision à prendre à chaque instant, entre explorer ou suivre les autres bateaux. En outre, il se trouve que, techniquement, la condition de compacité des images de la correspondance décrivant le processus de décision n'est pas satisfaite pour pouvoir appliquer tel quel le théorème de viabilité. Cette difficulté est levée dans le cadre de ce modèle des pêcheurs, et l'algorithme de calcul est explicité