A generalized configuration is a set of n points and (n 2 ) pseudolines such that each pseudoline passes through exactly two points, two pseudolines intersect exactly once, and no three pseudolines are concurrent. Following the approach of allowable sequences we prove a recursive inequality for the number of (≤ k)-sets for generalized configurations. As a consequence we improve the previously b...

0. Introduction 336 1. Main results 337 1.1. Semisimple groups 337 1.2. Factorization problem 338 1.3. Total positivity 339 1.4. Generalized minors 339 1.5. The twist maps 340 1.6. Formulas for factorization parameters 341 1.7. Total positivity criteria 343 1.8. Fundamental determinantal identities 343 2. Preliminaries 344 2.1. Involutions 344 2.2. Commutation relations 345 2.3. Generalized det...

Let V be Euclidean space. Let W ⊂ GL(V ) be a finite irreducible reflection group. Let A be the corresponding Coxeter arrangement. Let S be the algebra of polynomial functions on V. For H ∈ A choose αH ∈ V ∗ such that H = ker(αH). The arrangement A is known to be free: the derivation module D(A) = {θ ∈ DerS | θ(αH ) ∈ SαH} is a free S-module with generators of degrees equal to the exponents of ...

Motivated by a scheduling problem encountered in multicast environments, we study a vertex labelling problem, called Directed Circular Arrangement (DCA), that requires one to find an embedding of a given weighted directed graph into a discrete circle which would minimize the total weighted arc length. Its decision version is already known to be NP-complete when restricted to sparse weighted dir...

Since but little work has been done on the innervation of the esophagus, it seemed to me that it might be both interesting and profitable to determine, by means of the inlru-&am methylene blue method, the arrangement and terminations of the nerves in this part of the digestive tract, to verify the results already gained by other methods and, so far as practicable, to compare the innervation of ...

Hyperplane arrangements are very interesting combinatorial objects and many results can be found in the literature. For instance, several papers [1, 2, 6, 7] are concerned with the characteristic polynomials and the number of regions of a hyperplane arrangement. In his paper [9], Stanley reviewed various hyperplane arrangements raising interesting questions, one of which is related to the follo...

s of the Talks......................................................18 Abstracts of the Posters...................................................45s of the Posters...................................................45 Participants List............................................................55 Scientific and Social Program of QSCP-XXII...............Back Cover Map of the venue..................

OBJECTIVES Theoretically inspired by discursive institutionalism and multi-level governance, this paper assesses the extent to which 'environmental health' has emerged as a new discourse at European level, the effects it has had on national public health governance in two European countries, and what mechanisms have triggered or hindered these effects. STUDY DESIGN Comparison of the dynamics ...