Object-oriented languages provide advantages such as reuse and modularity, but they also raise new challenges for program verification. Program logics have been developed for languages such as C# and Java. However, these logics do not cover the specifics of the Eiffel language. This paper presents a program logic for Eiffel that handles exceptions, once routines, and multiple inheritance. The l...

This paper presents a real-time implementation of an automatic dialogue system called ‘Senior Companion’, which is not strictly task-oriented, but instead it is designed to ‘chat’ with elderly users about their family photographs. To a large extent, this task has lost the usual restriction of dialogue systems to a particular (narrow) domain, and thus the speech and natural language processing c...

Izmestiev and Joswig described how to obtain a simplicial covering space (the partial unfolding) of a given simplicial complex, thus obtaining a simplicial branched cover [Adv. Geom. 3(2):191-255, 2003]. We present a large class of branched covers which can be constructed via the partial unfolding. In particular, for d ≤ 4 every closed oriented PL d-manifold is the partial unfolding of some pol...

Let Σg,r be a compact oriented surface of genus g with r boundary components. We determine the abelianization of the symmetric mapping class group M̂(g,r)(p2) of a double unbranched cover p2 : Σ2g−1,2r → Σg,r using the Riemann constant, Schottky theta constant, and the theta multiplier. We also give lower bounds of the abelianizations of some finite index subgroups of the mapping class group.

Let l be an oriented link of d components with nonzero Alexander polynomial ∆(u1, . . . , ud). Let Λ be a finite-index subgroup of H1(S− l) ∼= Z, and let MΛ be the corresponding abelian cover of S branched along l. The growth rate of the order of the torsion subgroup of H1(MΛ), as a suitable measure of Λ approaches infinity, is equal to the Mahler measure of ∆.

Capitalizing and diffusing experience about multiagent systems are two key mechanisms the classical approach of methods and tools can’t address. Our hypothesis is that, among available techniques that collect and formalise experience, design patterns are the most able technique allowing to express the agent concepts and to adapt itself to the various MAS developing problems. In this paper, we p...

We consider various hitting and piercing problems for the family of axis-parallel rectangles induced by a point set. Selection Lemmas on induced objects are classical results in discrete geometry that have been well studied and have applications in many geometric problems like weak epsilon nets and slimming Delaunay triangulations. Selection Lemma type results typically bound the maximum number...

A common subproblem of $DNF$ approximate counting and derandomizing $RL$ is the discrepancy problem for combinatorial rectangles. We explicitly construct a $poly(n)$size sample space that approximates the volume of any combinatorial rectangle in $[n]^n$ to within $o(1)$ error (improving on the constructions of [EGLNV92]). The construction extends the techniques of [LLSZ95] for the analogous hit...

The problem of finding an optimal vertex cover in a graph is a classic NP-complete problem, and is a special case of the hitting set question. On the other hand, the hitting set problem, when asked in the context of induced geometric objects, often turns out to be exactly the vertex cover problem on restricted classes of graphs. In this work we explore a particular instance of such a phenomenon...