In this article, we introduce the concept of co-covering which is the dual of covering concept. Then, we prove several theorems being similar to the theorems that have been de-veloped for the covering concept. For example, we provide the lifting criterion for co-coverings of a topological space X, which helps us to classify them by subgroups of the group of all homeomorphisms of X.

Let [Kx, K2, ■ ■ ■ } be a class of compact convex subsets of euclidean M-space with the property that the set of their diameters is bounded. It is shown that the sets A, can be rearranged by the application of rigid motions so as to cover the total space if and only if the sum of the volumes of all the sets A, is infinite. Also, some statements regarding the densities of such coverings are prov...

Introduction. In this paper we present two results on branched coverings of Grassmannians.

The SARS-CoV-2 pandemic led to an unprecedented demand for PPE and generated a small-scale industry making personalised face coverings. Concerns had been raised about the use of natural rubber latex (NRL) as elastomeric material, with its health risks. We have investigated levels four NRL allergens total protein in ear-straps manufactured coverings material sold their production, number importe...

In the COVID--19 pandemic, among more controversial issues is use of masks and face coverings. Much concern boils down to question -- just how effective are coverings? One means address this review our understanding physical mechanisms by which coverings operate steric interception, inertial impaction, diffusion electrostatic capture. We enquire as what extent these can be used predict efficacy...

INTRODUCTION Prehospital maritime transportation in northern areas sets high demands on hypothermia prevention. To prevent body cooling and hypothermia of seriously-ill or injured casualties during transportation, casualty coverings must provide adequate thermal insulation and protection against cold, wind, moisture, and water splashes. OBJECTIVE The aim of this study was to determine the the...

In this paper we discuss open problems concerning L-invariants focusing on approximation by towers of finite coverings.

We prove that for every k > 1, there exist k-fold coverings of the plane (1) with strips, (2) with axis-parallel rectangles, and (3) with homothets of any fixed concave quadrilateral, that cannot be decomposed into two coverings. We also construct, for every k > 1, a set of points P and a family of disks D in the plane, each containing at least k elements of P , such that no matter how we color...

This exploratory paper considers the notion of a covering configuration and $G$-coverings which are coverings that quotients under semi-regular group action. We consider prime configurations, those cannot $G$-cover other before considering orbiconfigurations. These generalized in spirit an orbifold. derive some specific results as to when configurations well orbiconfiguration is bad - is, it be...

In this paper we consider Γ → M̃ → M , a Galois covering with boundary and D̃/, a Γ-invariant generalized Dirac operator on M̃ . We assume that the group Γ is of polynomial growth with respect to a word metric. By employing the notion of noncommutative spectral section associated to the boundary operator D̃/0 and the b-calculus on Galois coverings with boundary, we develop a higher Atiyah-PatodiSin...