Matej Bel University

About: Matej Bel University is a education organization based out in Banská Bystrica, Slovakia. It is known for research contribution in the topics: Tourism & Fuzzy set. The organization has 721 authors who have published 1497 publications receiving 11573 citations. The organization is also known as: Matej Bel & Univerzita Mateja Bela.

A Fresh Perspective on Canonical Extensions for Bounded Lattices

Abstract: This paper presents a novel treatment of the canonical extension of a bounded lattice, in the spirit of the theory of natural dualities. At the level of objects, this can be achieved by exploiting the topological representation due to M. Ploscica, and the canonical extension can be obtained in the same manner as can be done in the distributive case by exploiting Priestley duality. To encompass both objects and morphisms the Ploscica representation is replaced by a duality due to Allwein and Hartonas, recast in the style of Ploscica’s paper. This leads to a construction of canonical extension valid for all bounded lattices, which is shown to be functorial, with the property that the canonical extension functor decomposes as the composite of two functors, each of which acts on morphisms by composition, in the manner of hom-functors.

Formation of deuterons by coalescence: Consequences for deuteron number fluctuations

Abstract: Two scenarios for cluster production have long been discussed in the literature: (i) direct emission of the clusters from a (grand-canonical) thermal source or (ii) subsequent formation of the clusters by coalescence of single nucleons. While both approaches have been successfully applied in the past it has not yet been clarified which of the two mechanisms dominates the cluster production. We propose to use recently developed event-by-event techniques to study particle multiplicity fluctuations on nuclear clusters and employ this analysis to the deuteron number fluctuations to disentangle the two production mechanisms. We argue that for a grand-canonical cluster formation, the cluster fluctuations will follow Poisson distribution, while for the coalescence scenario, the fluctuations will strongly deviate from the Poisson expectation. We estimate the effect to be 10% for the variance and up to a factor of 5 for the kurtosis of the deuteron number multiplicity distribution. Our prediction can be tested in the beam energy scan program at the BNL Relativistic Heavy Ion Collider as well as experiments at the GSI Facility for Antiproton and Ion Research and the Nuclotron-based Ion Collider Facility.

Archimedean maps of higher genera

Abstract: The paper focuses on the classification of vertex-transitive polyhedral maps of genus from 2 to 4. These maps naturally generalise the spherical maps associated with the classical Archimedean solids. Our analysis is based on the fact that each Archimedean map on an orientable surface projects onto a oneor a two-vertex quotient map. For a given genus g ≥ 2 the number of quotients to consider is bounded by a function of g. All Archimedean maps of genus g can be reconstructed from these quotients as regular covers with covering transformation group isomorphic to a group G from a set of g-admissible groups. Since the lists of groups acting on surfaces of genus 2, 3 and 4 are known, the problem can be solved by a computer-aided case-to-case analysis.