In this paper, we consider a variation on Cheeger numbers related to the coboundary expanders recently defined by Dotterer and Kahle. A Cheeger-type inequality is proved, which is similar to a result on graphs due to Fan Chung. This inequality is then used to study the relationship between coboundary expanders on simplicial complexes and their corresponding eigenvalues, complementing and extend...

The subject of this paper is the derivation of the integrated Sachs-Wolfe (iSW) effect in cosmologies with coupled dark matter and dark energy fluids. These couplings influence the iSWeffect in three ways: The Hubble function assumes a different scaling, the structure growth rate shows a different time evolution, and in addition, the Poisson equation, which relates the density perturbations to ...

We show some sufficient conditions on a Banach space X concerning the generalized James constant, the generalized Jordan-von Neumann constant, the generalized Zbagănu constant, the coefficient ε̃0 X , the weakly convergent sequence coefficientWCS X , and the coefficient of weak orthogonality, which imply the existence of fixed points for multivalued nonexpansive mappings. These fixed point theor...

In this paper we propose James–Stein type estimators for variances raised to a fixed power by shrinking individual variance estimators towards the arithmetic mean. We derive and estimate the optimal choices of shrinkage parameters under both the squared and the Stein loss functions. Asymptotic properties are investigated under two schemes when either the number of degrees of freedom of each ind...

Lexical (and structural) ambiguities make language as expressive as it is. Computational lexicons thus have to cope with a large amount of polysemous words. Research in the last decade (e. g., Pustejovsky (1995), Kilgarriff and Gazdar (1995)) has aimed at identifying different types of polysemy in order to capture underlying regularities. This paper deals with a subtype of regular polysemy illu...