We present an optimal parallel algorithm to construct the well-separated pair decomposition of a point set P in < d. We show how this leads to a deterministic optimal O(logn) time parallel algorithm for nding the k-nearest-neighbors of each point in P, where k is a constant. We discuss several additional applications of the well-separated pair decomposition for which we can derive faster parall...

Let S be a set of points in R. Given a geometric spanner graph, G = (S, E), with constant dilation t, and a positive constant ε, we show how to construct a (1 + ε)-spanner of G with O(|S|) edges in time O(|E|+ |S| log |S|). Previous algorithms require a preliminary step in which the edges are sorted in non-decreasing order of their lengths and, thus, have running time Ω(|E| log |S|). We obtain ...

Eg̃eciog̃lu and Remmel [2] gave an interpretation for the entries of the inverse Kostka matrix K in terms of special rim-hook tableaux. They were able to use this interpretation to give a combinatorial proof that KK = I but were unable to do the same for the equation KK = I. We define a sign-reversing involution on rooted special rim-hook tableaux which can be used to prove that the last column o...

evelopmentally each lung-bud projects into the pleural coelom. The splanchnopleuric layer of lateral plate mesoderm invests each lung-bud and develops into pulmonary pleura. The right principal bronchus divides into three secondary bronchi, around which the lobes of the lungs are developed. The left principal bronchus divides into two secondary bronchi, around which the two lobes of the left lu...

I take the first part of the title of my essay from a character in Mary Wroth’s Urania , dubbed the Lady of the Oddest Passion, who makes a fleeting appearance in book 3. 1 This lady, described as “most loving, most discreet” (452), is loved by, and in return loves equally, two men. All three were content with this situation for a time, but ultimately the Lady is pressed to choose between the s...

This article examines explanations for both Internet use and non-use by older individuals. Older adults are often considered a homogeneous group with uniform reasons for Internet non-use, or when they are online, practising a uniform range of activities. The study gathered data concerning senior non-users through a national telephone survey. Data concerning senior Internet users were obtained t...

Telling stories is different from reading out text: a speaker reponds to the listener’s feedback and incorporates this into the ongoing talk. However, current computer systems are unable to do this and instead just non-attentively read out a text, disregarding all feedback (or the absence thereof). I propose and discuss an idea for a small research project and a plan for how an attentive listen...

Completely iterative theories of Calvin Elgot formalize (potentially infinite) computations as solutions of recursive equations. One of the main results of Elgot and his coauthors is that infinite trees form a free completely iterative theory. Their algebraic proof of this result is extremely complicated. We present completely iterative algebras as a new approach to the description of free comp...

The common bile acids of rat bile (chenodeoxycholic, hyodeoxycholic, cholic, alpha-muricholic, and beta-muricholic acids) are completely separated by a new thin-layer chromatographic system.