A Metric Inequality for the Thompson and Hilbert Geometries

There are two natural metrics defined on an arbitrary convex cone: Thompson's part metric and Hilbert's projective metric. For both, we establish an inequality giving information about how far the metric is from being non-positively curved.Comment: 15 pages, 0 figures. To appear in J. Inequalities Pure Appl. Mat

Mesh Gradation Control

. This paper gives a procedure to control the size variation in a mesh adaption scheme where the size specification (the so-called control space) is used to govern the mesh generation stage. The method consists in replacing the initial control space by a reduced one by means of size or metric. It allows to improve, a priori, the quality of the adapted mesh and to speed up the adaption procedure. Several numerical examples show the efficiency of the reduction scheme. 1 Introduction The first stage in an adaptive finite element scheme (cf. [7, 2]) consists in creating an initial mesh of a given domain\Omega\Gamma which is used to perform an initial computation (for example a flow solver). A size specification field is deduced (e.g. at the vicinity of each mesh vertex, the desired mesh size is specified), based on the numerical results. If the mesh does not satisfy the size specification field, then a new constrained mesh, governed by this field, is constructed. The size specification fie..

MLdonkey, a Multi-Network Peer-to-Peer File-Sharing Program (Extended Abstract)

April 2, 2003] Fabrice Le Fessant Microsoft Research lab

Boolean Constraint Solving Using clp(FD)

We present a boolean constraint logic language clp(B/FD) built upon a language over finite domains clp(FD) which uses a local propagation constraint solver. It is based on a single primitive constraint which allows the boolean solver to be encoded at a low-level. The boolean solver obtained in this way is both very simple and very efficient: on average it is eight times faster than the CHIP propagation-based boolean solver, i.e. nearly an order of magnitude faster, and infinitely better than the CHIP boolean unification solver. It also performs on average several times faster than special-purpose stand-alone boolean solvers

Asymptotic Analysis of Heaps of Pieces and application to Timed Petri Nets\Lambda

Heap models, where solid blocks are piled up accordingto the Tetris game mechanism, are a good model of Discrete Event Dynamic Systems. They offer a trade-off betweenmodeling power and tractability: on the one hand, timed 1- bounded Petri nets can be represented by heap models [20];on the other hand, the height of a heap can be computed by a max-plus automaton [5, 19], which can be analyzed viaspectral theory techniques [1, 18, 19]