The complexity of coloring graphs without long induced paths

We discuss the computational complexity of determining the chromatic number of graphs without long induced paths. We prove NP-completeness of deciding whether a P8-free graph is 5-colorable and of deciding whether a P12-free graph is 4-colorable. Moreover, we give a polynomial time algorithm for deciding whether a P5-free graph is 3-colorable

A Cryptographic Moving-Knife Cake-Cutting Protocol

This paper proposes a cake-cutting protocol using cryptography when the cake is a heterogeneous good that is represented by an interval on a real line. Although the Dubins-Spanier moving-knife protocol with one knife achieves simple fairness, all players must execute the protocol synchronously. Thus, the protocol cannot be executed on asynchronous networks such as the Internet. We show that the moving-knife protocol can be executed asynchronously by a discrete protocol using a secure auction protocol. The number of cuts is n-1 where n is the number of players, which is the minimum.Comment: In Proceedings IWIGP 2012, arXiv:1202.422

On Heads and Coordination in Valence Acquisition

Abstract. The aim of this paper is to present the design of a partial syntactic annotation of the IPI PAN Corpus of Polish [22] and the cor-responding extension of the corpus search engine Poliqarp [25,12] devel-oped at the Institue of Computer Science PAS and currently employed in Polish and Portuguese corpora projects. In particular, we will argue for the need to distinguish between, and represent both, syntactic and se-mantic heads, and we will sketch the representation of coordination, the area traditionally controversial both in theoretical and in computational linguistics. The annotation is designed in a way intended to maximise the usefulness of the resulting corpus for the task of automatic valence acquisition

Basic notions of information structure

This article takes stock of the basic notions of Information Structure (IS). It first provides a general characterization of IS — following Chafe (1976) — within a communicative model of Common Ground(CG), which distinguishes between CG content and CG management. IS is concerned with those features of language that concern the local CG. Second, this paper defines and discusses the notions of Focus (as indicating alternatives) and its various uses, Givenness (as indicating that a denotation is already present in the CG), and Topic (as specifying what a statement is about). It also proposes a new notion, Delimitation, which comprises contrastive topics and frame setters, and indicates that the current conversational move does not entirely satisfy the local communicative needs. It also points out that rhetorical structuring partly belongs to IS.Peer Reviewe