Given a finite point set P ⊂ R, we call a multiset A a one-sided weak ε-approximant for P (with respect to convex sets), if |P ∩ C|/|P | − |A ∩C|/|A| ≤ ε for every convex set C. We show that, in contrast with the usual (two-sided) weak ε-approximants, for every set P ⊂ R there exists a one-sided weak ε-approximant of size bounded by a function of ε and d.

In this paper we introduce the notion of the fractional weak discrepancy of a poset, building on previous work on weak discrepancy in [5, 8, 9]. The fractional weak discrepancy wdF (P ) of a poset P = (V,≺) is the minimum nonnegative k for which there exists a function f : V → R satisfying (1) if a ≺ b then f(a) + 1 ≤ f(b) and (2) if a ‖ b then |f(a)− f(b)| ≤ k. We formulate the fractional weak...

The synthesis and characterization of some new binuclear copper (II) complexes, based on the use of large, pyrole-containing macrocycles, the so called "expanded porphyrins", [Cu2(macrocycle)]+4 is described. Electron Spin Resonance (ESR) studies indicate a weak "half-field line", which is characteristic of the Cu(II)-Cu(II) dimer, is observed at about 1600G. The obser...

This work presents a novel approach for proximity queries in dynamic point sets, a common problem in computer graphics. We introduce the notion of Orthant Neighborhood Graphs, yielding a simple, decentralized spatial data structure based on weak spanners. We present efficient algorithms for dynamic insertions, deletions and movements of points, as well as range searching and other proximity que...

The paper introduces a new approach to preference structure, where from a weak preference relation derive the following relations:strict preference, indifference and incomparability, which by aggregations and negations are created and examined. We decomposing a preference relation into a strict preference, anindifference, and an incomparability relation.This approach allows one to quantify diff...

Entwined structures (A,C, ψ) were introduced by Brzeziński and Majid to study the interdependence of an R-algebra A and an R-coalgebra C, R a commutative ring. It turned out that this relationship can also be expressed by the fact that A⊗R C has a canonical A-coring structure. More generally weak entwined structures and their modules were studied by Caenepeel and Groot and it was suggested by C...

For small involutive and integral quantaloids Q it is shown that covariant presheaves on symmetric Q-categories are equivalent to certain subalgebras of a speci c monad on the category of symmetric Q-categories. This construction is related to a weakening of the subobject classi er axiom which does not require the classi cation of all subalgebras, but only guarantees that classi able subalgebra...