Actions, length functions, and non-archemedian words

In this paper we survey recent developments in the theory of groups acting on $\Lambda$-trees. We are trying to unify all significant methods and techniques, both classical and recently developed, in an attempt to present various faces of the theory and to show how these methods can be used to solve major problems about finitely presented $\Lambda$-free groups. Besides surveying results known up to date we draw many new corollaries concerning structural and algorithmic properties of such groups.Comment: 135 pages, 18 figures. arXiv admin note: substantial text overlap with arXiv:0911.0209, arXiv:0907.2356, arXiv:1208.4640, arXiv:1107.042

Infinite words and universal free actions

This is the second paper in a series of three, where we take on the unified theory of non-Archimedean group actions, length functions and infinite words. Here, for an arbitrary group $G$ of infinite words over an ordered abelian group $\Lambda$ we construct a $\Lambda$-tree $\Gamma_G$ equipped with a free action of $G$. Moreover, we show that $\Gamma_G$ is a universal tree for $G$ in the sense that it isometrically embeds in every $\Lambda$-tree equipped with a free $G$-action compatible with the original length function on $G$.Comment: 20 pages, 4 figure

A study of the Markov game approach to tactical maneuvering problems

Application of Markov game approach to planar air combat problem

Les conflits interétatiques dans les Amériques

This paper introduces two studies on the geopolitics and the conflicts in Latin America. The first part comprises a survey of the conflicts - most of which non-violent - which divide Latin America and oppose its states on an ideological basis, on a finality which would lead to hegemony, on territorial claims, or for reasons due to the impact of migration. The second part deals with the split between the Latin states and the new Anglophone states of the Caribbean, a split which has been bred by the differences in histories, institutions, and political representations, a split which has become apparent in the stands taken, namely in the Falkland crisis and in the border disputes between Venezuela and Guyana, and between Belize and Guatemala