We use powder x-ray diffraction under variable temperature to study the thermal expansion of metal–organic framework (MOF) PCN-222. The increases drastically in magnitude following more aggressive heating, which is rationalized by enhanced flexibility upon guest removal. Moreover, response strongly depends on temperature: volumetric expansivity nearly quadruples and along c changes sign cooling...

The aim of the KIDS1 project is the specification and generation/configuration of database management systems (DBMS). Thus, as for one aspect of KIDS, the modelling of potentially arbitrarily structured (generic) objects on different levels of abstraction has to be supported. First, a meta model provides for the description of data and operations close to the view of the user. Second, data are ...

Visual scenes contain information on both a local scale (e.g., a tree) and a global scale (e.g., a forest). The question of whether the visual system prioritizes local or global elements has been debated for over a century. Given that visual scenes often contain distinct individual objects, here we examine how regularities between individual objects prioritize local or global processing. Partic...

We develop a generalized triangle geometry, using an arbitrary bilinear form in an affine plane over a general field. By introducing standardized coordinates we find canonical forms for some basic centers and lines. Strong concurrencies formed by quadruples of lines from the Incenter hierarchy are investigated, including joins of corresponding Incenters, Gergonne, Nagel, Spieker points, Mittenp...

The purpose of this article is to define projections of ordered pairs, and to introduce triples and quadruples, and their projections. The theorems in this paper may be roughly divided into two groups: theorems describing basic properties of introduced concepts and theorems related to the regularity, analogous to those proved for ordered pairs by Cz. Byliński [1]. Cartesian products of subsets ...

We develop a generalized triangle geometry, using an arbitrary bilinear form in an affine plane over a general field. By introducing standardized coordinates we find canonical forms for some basic centers and lines. Strong concurrencies formed by quadruples of lines from the Incenter hierarchy are investigated, including joins of corresponding Incenters, Gergonne, Nagel, Spieker points, Mittenp...

The contact graph of an arbitrary finite packing of unit balls in Euclidean 3-space is the (simple) graph whose vertices correspond to the packing elements and whose two vertices are connected by an edge if the corresponding two packing elements touch each other. One of the most basic questions on contact graphs is to find the maximum number of edges that a contact graph of a packing of n unit ...

We characterize optimal solutions to the gossip problem in which no one hears his own information. That is, we consider graphs on n vertices where the edges are given a linear ordering such that an increasing path exists from each vertex to every other, but there is no increasing path from a vertex to itself. Such graphs exist if and only if n is even, in which case the fervest number of edges ...

We study cubic forms on F2 using the Hurwitz-Radon theory of square identities. As an application, we obtain the following elementary statement. Given a family F of subsets of an n-set such that the cardinality of the symmetric di↵erence of any two elements F,F 0 2 F is not a multiple of 4, the maximal size of F is bounded by 2n, unless n ⌘ 3 mod 4 when it is bounded by 2n + 2. We also apply th...

Abstract. We investigate several generalizations of the harmonic and refined Rayleigh–Ritz method. These may be practical when one is interested in eigenvalues close to one of two targets (for instance, when the eigenproblem has Hamiltonian structure such that eigenvalues come in pairs or quadruples), or in rightmost eigenvalues close to (for instance) the imaginary axis. Our goal is to develop...