W e present an optimal parallel algorithm t o construct the well-separated pair decomposition of a point set P in Zd. W e show how this leads to a deterministic opt imal O(1ogn) t ime parallel algorithm for finding the k nearest neighbors of each point in P, where k is a constant. W e discuss several additional applications of the well-separated pair decomposition for which we can derive fas t ...

Timothy Williamson’s Modal Logic as Metaphysics is, among much else, a detailed and complex defense of the metaphysical view he calls necessitism, the view that necessarily everything necessarily exists (is something), that although it may be a contingent matter how things are, what things there are is entirely a matter of necessity. The majority of contemporary modal metaphysicians reject this...

Strikingly, Ogawa and Wildasin (2009) find that in a model with heterogenous jurisdictions, interjurisdictional capital flows, and interjurisdictional environmental damage spillovers, decentralized planning outcomes are equivalent to that under a single centralized planner. Taken to its extreme this result renders international agreements such as the Kyoto Protocol irrelevant. We first show the...

Given a geometric graph G = (S,E) in R with constant dilation t, and a positive constant ε, we show how to construct a (1 + ε)-spanner of G with O(|S|) edges using O(sort(|E|)) memory transfers in the cacheoblivious model of computation. The main building block of our algorithm, and of independent interest in itself, is a new cache-oblivious algorithm for constructing a well-separated pair deco...

The fast multipole method (FMM) performs fast approximate kernel summation to a specified tolerance ǫ by using a hierarchical division of the domain, which groups source and receiver points into regions that satisfy local separation and the well-separated pair decomposition properties. While square tilings and quadtrees are commonly used in 2D, we investigate alternative tilings and associated ...

We present an external-memory algorithm to compute a well-separated pair decomposition (WSPD) of a given point set S in Rd in O(sort(N)) I/Os, where N is the number of points in S and sort(N) denotes the I/O-complexity of sorting N items. (Throughout this paper, we assume that the dimension d is fixed). As applications of the WSPD, we show how to compute a linear-size t-spanner for S within the...

In two studies the role of biomedical knowledge in the diagnosis of clinical cases was explored. Experiment 1 demonstrated a decrease in the use of biomedical knowledge with increasing expertise. This result appeared to be at variance with some findings reported in the literature (e.g., Lesgold. 1934). but supported those of others (e.g., Patel, Evans, & Groen, 1989). In Experiment 2, three pos...

http://gpi.sagepub.com/content/10/3/373 The online version of this article can be found at: DOI: 10.1177/1368430207078697 2007 10: 373 Group Processes Intergroup Relations Peter Fischer, Tobias Greitemeyer and Andreas Kastenmüller Aggression Potential, and Attitudes Toward Terrorism About the Associations Between Muslims' Religiosity, Religious Identity, What Do We Think About Muslims? The Vali...

This paper was prepared for publication after the death of the author by T. Lewis, M.Sc. Professor R. A. Milne, F.R.S., has also seen the manuscript and makes the following observation: “ This paper should be published not only as an act of piety in Schott’s memory, but because it is done with intense care and skill and is throughout critical. Quantum physicists of the type who write the fashio...