The syntenic distance between two genomes is given by the minimum number of fusions, fissions, and translocations required to transform one into the other, ignoring the order of genes within chromosomes. Computing this distance is NP-hard. In the present work, we give a tight connection between syntenic distance and the incomplete gossip problem, a novel generalization of the classical gossip p...

A q-analog of a Steiner system (briefly, q-Steiner system), denoted by S = Sq[t, k, n], is a set of k-dimensional subspaces of F n q such that each t-dimensional subspace of Fq is contained in exactly one element of S. Presently, q-Steiner systems are known only for t = 1 and in the trivial cases t = k and k = n. In this paper, the first known nontrivial q-Steiner systems with t ≥ 2 are constru...

This paper considers the problem of finding a quickest path between two points in the Euclidean plane in the presence of a transportation network. A transportation network consists of a planar network where each road (edge) has an individual speed. A traveller may enter and exit the network at any point on the roads. Along any road the traveller moves with a fixed speed depending on the road, a...

Several power indices have been introduced in the literature in order to measure the influence of individual committee members on the aggregated decision. Here we ask the inverse question and aim to design voting rules for a committee such that a given desired power distribution is met as closely as possible. We present an exact algorithm for a large class of different power indices based on in...

Decomposable dependency models and their graphical counterparts, i.e., chordal graphs, possess a number of interesting and useful properties. On the basis of two character­ izations of decomposable models in terms of independence relationships, we develop an exact algorithm for recovering the chordal graphical representation of any given decom­ posable model. We also propose an algorithm for le...

Most Go-playing programs use a combination of search and heuristics based on an influence function to determine whether territories are safe. However, to assure the correct evaluation of Go positions, the safety of stones and territories must be proved by an exact method. The first exact algorithm, due to Benson [1], determines the unconditional safety of stones and territories. Müller [3] deve...

In this note we present an efficient exact algorithm to solve the joint pricing and inventory problem for which Bhattacharjee and Ramesh (2000) proposed two heuristics. Our algorithm appears to be superior also in terms of computation time. Furthermore, we point out several mistakes in the paper by Bhattacharjee and Ramesh.

We have compared the high resolution BGO detector blocks from the EXACT HR PET system which use two dual-cathode rectangular photomultiplier (PM) tubes with a new block design, the EXACT HR PLUS, which uses four round PM tubes. Despite the lower coupling area between photocathode and scintillator, the HR PLUS block compares favorably with the HR block. The energy resolution averages 20% for the...