Two remarks on equivelar manifolds

It has been pointed out that a construction for equivelar polyhedral manifolds described in an earlier paper by the present authors may possibly not be performed; an alternative construction is given here. Further, it is shown that certain equivelar polyhedra cannot have equiangular (and hence regular) faces.     

Baryon magnetic moments in a dynamical quark-diquark model

The magnetic moments of baryons are calculated in a dynamical quark-diquark model using current-quark masses as input. Except for theΞ ^? moment, results are in fairly good agreement with experiment.     

On Blaschke's extension of Bonnesen's inequality

W. Blaschke established a Bonnesen-style inequality for the relative inradius and circumradius of a planar convex bodyK with respect to another. We sharpen this inequality by considering the radii of the minimal convex annulus ofK.     

Existence of Feller Cocycles on a C*-Algebra

The quantum stochastic differential equation is considered on a unital C^*-algebra, with separablenoise dimension space. Necessary conditions on the matrix ofbounded linear maps for the existence of a completely positivecontractive solution are shown to be sufficient. It is knownthat for completely positive contraction processes, k satisfiessuch an equation if and only if k is a regular Markovian cocycle.‘Feller’ refers to an invariance condition analogousto probabilistic terminology if the algebra is thought of asa non-commutative topological space. 2000 Mathematics SubjectClassification 81S25, 46L07, 46L53, 47D06.     

The combinatorially regular polyhedra of index 2

Summary We investigate polyhedral realizations of regular maps with self-intersections in E³, whose symmetry group is a subgroup of index 2 in their automorphism group. We show that there are exactly 5 such polyhedra. The polyhedral sets have been more or less known for about 100 years; but the fact that they are realizations of regular maps is new in at least one case, a self-dual icosahedron of genus 11. Our polyhedra are closely related to the 5 regular compounds, which can be interpreted as discontinuous polyhedral realizations of regular maps.The author was born on March 5, 1937; so exactly half a century after Otto Haupt.Dedicated to Professor Otto Haupt with best wishes on his 100th birthday.     

Asymptotic behaviour and reduction of couplings for models including nonrenormalizable interactions

We study equivalence relations among parametrizations of models including nonrenormalizable polynomial interactions. The method of reduction of couplings allows for a classification of the parameter associated to the nonrenormalizable perturbations and stability considerations. The relation to effective models is briefly discussed.     

Gitterpunktanzahl konvexer Rotationskörper

Ohne Zusammenfassung