Several approaches to the matter creation problem in the context of cosmological models are summarily reviewed. A covariant formulation of the general relativistic imperfect simple fluid endowed with a process of matter creation is presented. By considering the standard big bang model, it is shown how the recent results of Prigogine et alii [1] can be recovered and, at the same time their limit...

pour l'honneur qu'ils me font en participant à ce Jury, et particulièrement Messieurs João Silva et Gilles Muller qui ont accepté la charge d'être rapporteurs. J'exprime ma gratitude à João Silva pour qui la langue dans laquelle est rédigé ce manuscrit a représenté une charge de travail supplémentaire. Ces travaux ont été partiellement financés par la Communauté Européenne dans le cadre du proj...

The poison frog genus Ameerega (Dendrobatidae) currently contains 32 species. They are distributed from central Brazil into western Amazonia to the lower Andean versant. In addition, three trans-Andean species have been allocated to Ameerega (Andrade et al. 2013; Frost 2014). Ameerega berohoka (Vaz-Silva & Maciel 2011) was described based on specimens from central Brazil (type-locality: Arenópo...

Introduction In multi-agent systems (MAS) roles are an important issue since they define responsibilities and obligations to the agents, i.e. they guide and restrict the behaviors of agents in a social context [Silva et al., 2004b]. Several agent oriented software methodologies such as MESSAGE [Caire et al., 2002], GAIA [Wooldridge et al., 2000] and TROPOS [Mylopoulos et al., 2001], modeling la...

We study extensional models of the untyped lambda calculus in the setting of the game semantics introduced by Abramsky, Hyland et alii. In particular we show that, somewhat unexpectedly and contrary to what happens in ordinary categories of domains, all reflexive objects in a standard category of games, induce the same λ-theory. This is H∗, the maximal theory induced already by the classical C....

In this paper we show how to solve the Maximum Weight Stable Set Problem in a claw-free graph G(V,E) with α(G) ≤ 3 in time O(|E| log |V |). More precisely, in time O(|E|) we check whether α(G) ≤ 3 or produce a stable set with cardinality at least 4; moreover, if α(G) ≤ 3 we produce in time O(|E| log |V |) a maximum stable set of G. This improves the bound of O(|E||V |) due to Faenza et alii ([2]).