English) Recently there have been several attempts to provide a whole set of generators of the ideal of the algebraic variety associated to a phylogenetic tree evolving under an algebraic model. These algebraic varieties have been proven to be useful in phylogenetics. In this paper we prove that, for phylogenetic reconstruction purposes, it is enough to consider generators coming from the edges...

L’analyse en ligne OLAP (On Line Analytical Processing) soutient les entrepôts de données dans le processus d’aide à la décision. Cependant, il n’existe pas d’outils pour guider l’utilisateur dans l’exploration, ni pour approfondir l’analyse vers l’explication et la prédiction. Dans un processus décisionnel, un utilisateur peut vouloir anticiper la réalisation d’évènements futurs. Le couplage d...

We study the combinatorics of weighted trees from the point of view of tropical algebraic geometry and tropical linear spaces. The set of dissimilarity vectors of weighted trees is contained in the tropical Grassmannian, so we describe here the tropical linear space of a dissimilarity vector and its associated family of matroids. This gives a family of complete flags of tropical linear spaces, ...

Dyck tilings were introduced by Kenyon and Wilson in their study of double-dimer pairings. They are certain kinds of tilings of skew Young diagrams with ribbon tiles shaped like Dyck paths. We give two bijections between “cover-inclusive” Dyck tilings and linear extensions of tree posets. The first bijection maps the statistic (area + tiles)/2 to inversions of the linear extension, and the seco...

We study random walks on undirected graphs with weighted edges. Our main result shows that any spanning tree deened by the edges corresponding to a rst visit of a vertex, appears with a probability proportional to its weight, which is the product of the weights of its edges. This provides an algorithm for generating non uniform random spanning trees in a weighted graph. The technique used here ...

— Our model of computation is a parallel computer with k synchronized processors Pu . . . , Pk sharing a common random access storage, where simultaneous access to the same storage location by two or more processors is not allowed. Suppose a 2-3 tree Twith n leaves is implemented in the storage, suppose au ..., ak are data that may or may not be stored in the leaves, suppose ö! ̂ . . . ^ak and f...

This paper deals with several lexicographic problems arising from the choice of hypernyms in the Dictionary of Medieval Scientific French (Créalscience database). The generic names used by medieval scholars indicate categorizations which differ from modern classifications. We examine some cases selected from the medieval domain of natural sciences where we can notice a conceptual discrepancy be...

This paper is primarily concerned with motion-compensated interpolation of video sequences using multiple images. Due to the extended temporal support of such motion compensation, linear (constant-velocity) trajectory model is often inappropriate, for example due to insuucient temporal sampling. Recently, we have proposed a quadratic (constant-acceleration) trajectory model and a framework for ...