We investigate concurrency as unifying computational paradigm which integrates functional, constraint, and object-oriented programming. We propose the-calculus as a uniform foundation of concurrent computation and formally relate it to other models: The-calculus with equational constraints provides for logic variables and is bisimilar to the-calculus. The-calculus without constraints is a prope...

We consider scheduling of colored packets with transition costs which form a general metric space. We design 1 − O (√ MST (G) L ) competitive algorithm. Our main result is an hardness result of 1 − Ω (√ MST (G) L ) which matches the competitive ratio of the algorithm for each metric space separately. In particular we improve the hardness result of Azar at el. for uniform metric space. We also e...

Using labelled formulae, a cut-free sequent calculus for intuitionistic propositional logic is presented, together with an easy cut-admissibility proof; both extend to cover, in a uniform fashion, all intermediate logics characterised by frames satisfying conditions expressible by one or more geometric implications. Each of these logics is embedded by the Gödel-McKinsey-Tarski translation into ...

In this paper, we present a data hiding algorithm for binary document images. This algorithm is based on the DistanceReciprocal Distortion Measure [1] that is used to evaluate the amount of distortion caused by flipping a particular pixel in binary document images. The pixels that will cause less distortion after flipping are preferred candidates for flipping. We do the embedding by enforcing t...

We present geometric conditions on a metric space (Y, dY ) ensuring that almost surely, any isometric action on Y by Gromov’s expander-based random group has a common fixed point. These geometric conditions involve uniform convexity and the validity of nonlinear Poincaré inequalities, and they are stable under natural operations such as scaling, Gromov-Hausdorff limits, and Cartesian products. ...

It has been proved that sphericity testing for digraphs is an NP-complete problem. Here, we investigate sphericity of 3-connected single source digraphs. We provide a new combinatorial characterization of sphericity and give a linear time algorithm for sphericity testing. Our algorithm tests whether a 3-connected single source digraph with $n$ vertices is spherical in $O(n)$ time.

We construct a locally finite graph and a bounded geometry metric space which do not admit a quasi-isometric embedding into any uniformly convex Banach space. Connections with the geometry of c0 and superreflexivity are discussed. The question of coarse embeddability into uniformly convex Banach spaces became interesting after the recent work of G. Kasparov and G. Yu, who showed the coarse Novi...

We construct a locally finite graph and a bounded geometry metric space which do not admit a quasi-isometric embedding into any uniformly convex Banach space. Connections with the geometry of c0 and superreflexivity are discussed. The question of coarse embeddability into uniformly convex Banach spaces became interesting after the recent work of G. Kasparov and G. Yu, who showed the coarse Novi...