We examine the close analogy which exists between Helly graphs and hyperconvex metric spaces, and propose the hyperconvex semi-metric space as an unifying concept. Unlike the metric spaces, these semi-metric spaces have a rich theory in the discrete case. Apart from some new results on Helly graphs, the main results concern: fixed point property of contractible semi-metric spaces (for nonexpans...

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For a given concrete noun concept, humans are usually able to cite properties (e.g., elephant is animal, car has wheels) of that concept; cognitive psychologists have theorised that such properties are fundamental to understanding the abstract mental representation of concepts in the brain. Consequently, the ability to automatically extract such properties would be of enormous benefit to the fi...

A dimensional dual hyperoval satisfying property (H) [6] in a project!ve space of order 2 is naturally associated with a "semi-Boolean" Steiner quadruple system. The only known examples are associated with Boolean systems. For every d > 2, we construct a new ddimensional dual hyperoval satisfying property (H) in PG(d(d + 3)/2,2); its related semiBoolean system is the Teirlinck one. It is univer...

A. Summary of items most closely related to the proposal: (1) In [7] (The generalized Grassmann invariant ...), the PI introduces pictures, derives their basic properties, and uses them to construct an element of order 16 in K 3 (Z). (2) In [40] (Links, pictures and the homology of nilpotent groups), the PI, with Kent Orr, analyze picture for torsion free nilpotent groups and construct special ...

We present a comprehensive analysis of form factors for two light pseudoscalar mesons induced by scalar, vector, and tensor quark operators. The theoretical framework is based on combination unitarized chiral perturbation theory dispersion relations. low-energy constants in are fixed global fit to the available data two-meson scattering phase shifts. Each factor derived from improved iterativel...

A non-destructive cultivation system was developed to study the dynamics of phosphorus (Pi) uptake by mycorrhizal and non-mycorrhizal maize plantlets. The system consisted of a plant container connected via silicon tubes to a glass bottle containing a nutrient solution supplemented with Pi. The nutrient solution is pumped with a peristaltic pump to the upper part of the container via the silico...

An additive hereditary graph property is a class of simple graphs which is closed under unions, subgraphs and isomorphisms. If P1, . . . ,Pn are graph properties, then a (P1, . . . ,Pn)-decomposition of a graph G is a partition E1, . . . , En of E(G) such that G[Ei], the subgraph of G induced by Ei, is in Pi, for i = 1, . . . , n. The sum of the properties P1, . . . ,Pn is the property P1 ⊕ · ·...

A property of graphs is any class of graphs closed under isomorphism. A property of graphs is induced-hereditary and additive if it is closed under taking induced subgraphs and disjoint unions of graphs, respectively. Let P1,P2, . . . ,Pn be properties of graphs. A graph G is (P1,P2, . . . ,Pn)-partitionable (G has property P1◦P2◦ · · · ◦Pn) if the vertex set V (G) of G can be partitioned into ...

In this study a semi-automated image-processing based method was designed in which the parameters such as intima-media thickness (IMT), resistive index (RI), pulsatility index (PI), dicrotic notch index (DNI), and mean wavelet entropy (MWE) were evaluated in B-mode and Doppler ultrasound in patients presenting with carotid artery atherosclerosis. In a cross-sectional design, 144 men were divide...