@article{4100,
abstract = {This paper investigates the existence of linear space data structures for range searching. We examine thehomothetic range search problem, where a setS ofn points in the plane is to be preprocessed so that for any triangleT with sides parallel to three fixed directions the points ofS that lie inT can be computed efficiently. We also look atdomination searching in three dimensions. In this problem,S is a set ofn points inE 3 and the question is to retrieve all points ofS that are dominated by some query point. We describe linear space data structures for both problems. The query time is optimal in the first case and nearly optimal in the second.
},
author = {Chazelle, Bernard and Herbert Edelsbrunner},
journal = {Discrete & Computational Geometry},
number = {1},
pages = {113 -- 126},
publisher = {Springer},
title = {{Linear space data structures for two types of range search}},
doi = {10.1007/BF02187875},
volume = {2},
year = {1987},
}
@article{4319,
abstract = {The grasshopper Podisma pedestris contains two chromosomal races, which differ by a Robertsonian fusion between the sex chromosome and an autosome, and which meet in a narrow hybrid zone in the Alpes Maritimes. DNA content variation across this hybrid zone was investigated by optical densitometry of Feulgen stained spermatids. Spermatids from males with the unfused sex chromosome stain more strongly than those from males with the fused chromosome. The difference between the karyotypes is greater in the centre of the hybrid zone, suggesting that it is not a pleiotropic effect of the fusion itself, but is due instead to differences at closely linked loci.},
author = {Westerman, Michael and Nicholas Barton and Hewitt, Godfrey M},
journal = {Heredity},
pages = {221 -- 228},
publisher = {Nature Publishing Group},
title = {{Differences in DNA content between two chromosomal races of the grasshopper Podisma pedestris}},
doi = {10.1038/hdy.1987.36},
volume = {58},
year = {1987},
}
@book{3900,
abstract = {Computational geometry as an area of research in its own right emerged in the early seventies of this century. Right from the beginning, it was obvious that strong connections of various kinds exist to questions studied in the considerably older field of combinatorial geometry. For example, the combinatorial structure of a geometric problem usually decides which algorithmic method solves the problem most efficiently. Furthermore, the analysis of an algorithm often requires a great deal of combinatorial knowledge. As it turns out, however, the connection between the two research areas commonly referred to as computa tional geometry and combinatorial geometry is not as lop-sided as it appears. Indeed, the interest in computational issues in geometry gives a new and con structive direction to the combinatorial study of geometry. It is the intention of this book to demonstrate that computational and com binatorial investigations in geometry are doomed to profit from each other. To reach this goal, I designed this book to consist of three parts, acorn binatorial part, a computational part, and one that presents applications of the results of the first two parts. The choice of the topics covered in this book was guided by my attempt to describe the most fundamental algorithms in computational geometry that have an interesting combinatorial structure. In this early stage geometric transforms played an important role as they reveal connections between seemingly unrelated problems and thus help to structure the field.},
author = {Edelsbrunner, Herbert},
isbn = {9783540137221},
publisher = {Springer},
title = {{Algorithms in Combinatorial Geometry}},
volume = {10},
year = {1987},
}
@inproceedings{3514,
abstract = {We consider the problem of obtaining sharp (nearly quadratic) bounds for the combinatorial complexity of the lower envelope (i.e. pointwise minimum) of a collection of n bivariate (or generally multi-variate) continuous and "simple" functions, and of designing efficient algorithms for the calculation of this envelope. This problem generalizes the well-studied univariate case (whose analysis is based on the theory of Davenport-Schinzel sequences), but appears to be much more difficult and still largely unsolved. It is a central problem that arises in many areas in computational and combinatorial geometry, and has numerous applications including generalized planar Voronoi diagrams, hidden surface elimination for intersecting surfaces, purely translational motion planning, finding common transversals of polyhedra, and more. In this abstract we provide several partial solutions and generalizations of this problem, and apply them to the problems mentioned above. The most significant of our results is that the lower envelope of n triangles in three dimensions has combinatorial complexity at most O(n2α(n)) (where α(n) is the extremely slowly growing inverse of Ackermann's function), that this bound is tight in the worst case, and that this envelope can be calculated in time O(n2α(n)).},
author = {Herbert Edelsbrunner and Pach, János and Schwartz, Jacob T and Sharir, Micha},
pages = {27 -- 37},
publisher = {IEEE},
title = {{On the lower envelope of bivariate functions and its applications}},
doi = {10.1109/SFCS.1987.44},
year = {1987},
}
@article{3658,
abstract = {Females of the grasshopper Podisima pedestris were collected from the middle of a hybrid zone between two chromosomal races in the Alpes Maritimes. They had already mated in the field, and could therefore lay fertilised eggs in the laboratory. The embryos were karyotyped, and found to contain an excess of chromosomal homozygotes. No evidence of assortative mating was found from copulating pairs taken in the field. The excess appears to have been caused by a combination of multiple insemination and assortative fertilisation. The genetics of the assortment, and the implications for the evolution of reproductive isolation are discussed.},
author = {Hewitt, Godfrey M and Nichols, R. A. and Nicholas Barton},
journal = {Heredity},
number = {3},
pages = {457 -- 466},
publisher = {Nature Publishing Group},
title = {{Homogamy in a hybrid zone in the alpine grasshopper Podisma pedestris}},
doi = {10.1038/hdy.1987.156},
volume = {59},
year = {1987},
}
@article{3660,
abstract = {The maintenance of polygenic variability by a balance between mutation and stabilizing selection has been analysed using two approximations: the ‘Gaussian’ and the ‘house of cards’. These lead to qualitatively different relationships between the equilibrium genetic variance and the parameters describing selection and mutation. Here we generalize these approximations to describe the dynamics of genetic means and variances under arbitrary patterns of selection and mutation. We incorporate genetic drift into the same mathematical framework.
The effects of frequency-independent selection and genetic drift can be determined from the gradient of log mean fitness and a covariance matrix that depends on genotype frequencies. These equations describe an ‘adaptive landscape’, with a natural metric of genetic distance set by the covariance matrix. From this representation we can change coordinates to derive equations describing the dynamics of an additive polygenic character in terms of the moments (means, variances, …) of allelic effects at individual loci. Only under certain simplifying conditions, such as those derived from the Gaussian and house-of-cards approximations, do these general recursions lead to tractable equations for the first few phenotypic moments. The alternative approximations differ in the constraints they impose on the distributions of allelic effects at individual loci. The Gaussian-based prediction that evolution of the phenotypic mean does not change the genetic variance is shown to be a consequence of the assumption that the allelic distributions are never skewed. We present both analytical and numerical results delimiting the parameter values consistent with our approximations.},
author = {Nicholas Barton and Turelli, Michael},
journal = {Genetical Research},
number = {2},
pages = {157 -- 174},
publisher = {Cambridge University Press},
title = {{Adaptive landscapes, genetic distance, and the evolution of quantitative characters}},
doi = {10.1017/S0016672300026951},
volume = {49},
year = {1987},
}
@article{4101,
abstract = {In a number of recent papers, techniques from computational geometry (the field of algorithm design that deals with objects in multi-dimensional space) have been applied to some problems in the area of computer graphics. In this way, efficient solutions were obtained for the windowing problem that asks for those line segments in a planar set that lie in given window (range) and the moving problem that asks for the first line segment that comes into the window when moving the window in some direction. In this paper we show that also the zooming problem, which asks for the first line segment that comes into the window when we enlarge it, can be solved efficiently. This is done by repeatedly performing range queries with ranges of varying sizes. The obtained structure is dynamic and yields a query time of O(log2n) and an insertion and deletion time of O(log2n), where n is the number of line segments in the set. The amount of storage required is O(n log n). It is also shown that the technique of repeated range search can be used to solve several other problems efficiently.
},
author = {Herbert Edelsbrunner and Overmars, Mark H},
journal = {Information Processing Letters},
number = {6},
pages = {413 -- 417},
publisher = {Elsevier},
title = {{Zooming by repeated range detection}},
doi = {10.1016/0020-0190(87)90120-7},
volume = {24},
year = {1987},
}
@article{4322,
abstract = {A method is developed for calculating the probability of establishment of an allele which is favoured in some places, but not others, in a large subdivided population. This method is quite general, and could be used to calculate the chance that any system which is linear near an absorbing boundary will move away from that boundary. The results are applied to a population distributed along one dimension. Only mutants which arise within a distance σ/ √2s of the region in which they are favoured stand an appreciable chance of establishment. The net chance of establishment of mutations distributed randomly across the habitat will be decreased by gene flow if selection against them is sufficiently strong. However, if the mutations are only weakly deleterious outside some limited region, gene flow may increase the net chance of establishment.},
author = {Nicholas Barton},
journal = {Genetical Research},
number = {1},
pages = {35 -- 40},
publisher = {Cambridge University Press},
title = {{The probability of establishment of an advantageous mutation in a subdivided population}},
doi = {10.1017/S0016672300023314},
volume = {50},
year = {1987},
}
@article{3659,
author = {Charlesworth, Brian and Coyne, Jerry A and Nicholas Barton},
journal = {American Naturalist},
number = {1},
pages = {113 -- 146},
publisher = {University of Chicago Press},
title = {{The relative rates of evolution of sex chromosomes and autosomes.}},
volume = {130},
year = {1987},
}
@article{3661,
abstract = {We derive a formula giving thefrequency with which random drift shifts a population betweenalternativeequilibria. This formula is valid when such shifts are rare (Ns >> 1), and applies over a wide range of mutation rates. When the number of mutations entering the population is low (4Nμ << 1), the rate of stochastic shifts reduces to the product ofthe mutation rate and the probability of fixation of a single mutation. However, when many mutations enter the population in each generation (4Nμ >> 1), the rate is higher than would be expected if mutations were established independently, and converges to that given by a gaussian approximation. We apply recent results on bistable systems to extend this formula to the general multidimensional case. This gives an explicit expression for thefrequencyof stochastic shifts, which depends only on theequilibrium probability distribution near the saddle point separating thealternative stable states. The plausibility of theories of speciation through random drift are discussed in the light of these results.},
author = {Nicholas Barton and Rouhani, Shahin},
journal = {Journal of Theoretical Biology},
number = {4},
pages = {397 -- 418},
publisher = {Elsevier},
title = {{The frequency of shifts between alternative equilibria}},
doi = {10.1016/S0022-5193(87)80210-2},
volume = {125},
year = {1987},
}
@article{4094,
abstract = {The visibility graph of a finite set of line segments in the plane connects two endpoints u and v if and only if the straight line connection between u and v does not cross any line segment of the set. This article proves that 5n - 4 is a lower bound on the number of edges in the visibility graph of n nonintersecting line segments in the plane. This bound is tight.},
author = {Herbert Edelsbrunner and Shen, Xiaojun},
journal = {Information Processing Letters},
number = {2},
pages = {61 -- 64},
publisher = {Elsevier},
title = {{A tight lower bound on the size of visibility graphs}},
doi = {10.1016/0020-0190(87)90038-X},
volume = {26},
year = {1987},
}
@article{4102,
abstract = {Determining or counting geometric objects that intersect another geometric query object is at the core of algorithmic problems in a number of applied areas of computer science. This article presents a family of space-efficient data structures that realize sublinear query time for points, line segments, lines and polygons in the plane, and points, line segments, planes, and polyhedra in three dimensions.},
author = {Dobkin, David P and Herbert Edelsbrunner},
journal = {Journal of Algorithms},
number = {3},
pages = {348 -- 361},
publisher = {Academic Press},
title = {{Space searching for intersecting objects}},
doi = {10.1016/0196-6774(87)90015-0},
volume = {8},
year = {1987},
}
@article{3580,
abstract = {An edge-skeleton in an arrangementA(H) of a finite set of planes inE 3 is a connected collection of edges inA(H). We give a method that constructs a skeleton inO(√n logn) time per edge. This method implies new and more efficient algorithms for a number of structures in computational geometry including order-k power diagrams inE 2 and space cutting trees inE 3.
We also give a novel method for handling special cases which has the potential to substantially decrease the amount of effort needed to implement geometric algorithms.},
author = {Herbert Edelsbrunner},
journal = {Algorithmica},
number = {1-4},
pages = {93 -- 109},
publisher = {Springer},
title = {{Edge-skeletons in arrangements with applications}},
doi = {10.1007/BF01840438},
volume = {1},
year = {1986},
}
@article{3662,
abstract = {The evolution of the probabilities of genetic identity within and between tandemly repeated loci of a multigene family is investigated analytically and numerically. Unbiased intrachromosomal gene conversion, equal crossing over, random genetic drift, and mutation to new alleles are incorporated. Generations are discrete and nonoverlapping; the diploid, monoecious population mates at random. Under the restriction that there is at most one crossover in the multigene family per individual per generation, the dependence on location of the probabilities of identity is treated exactly. In the “homogeneous” approximation to this “exact” model, end effects are disregarded; in the “exchangeable” approximation, to which all previous work was confined, all position dependence is neglected. Numerical results indicate that (i) the exchangeable and homogeneous models are both qualitatively correct, (ii) the exchangeable model is sometimes too inaccurate for quantitative conclusions, and (iii) the homogeneous model is always more accurate than the exchangeable one and is always sufficiently accurate for quantitative conclusions.},
author = {Nagylaki, Thomas and Nicholas Barton},
journal = {Theoretical Population Biology},
number = {3},
pages = {407 -- 437},
publisher = {Academic Press},
title = {{Intrachromosomal gene conversion, linkage, and the evolution of multigene families}},
doi = {10.1016/0040-5809(86)90017-1},
volume = {29},
year = {1986},
}
@article{4103,
abstract = {Let A be an arrangement of n lines in the plane. Suppose F1,…, Fk are faces in the dissection induced by A and that Fi is a t(Fi)-gon. We give asymptotic bounds on the maximal sum ∑i=1kt(Fi) which can be realized by k different faces in an arrangement of n lines. The results improve known bounds for k of higher order than n(1/2).},
author = {Herbert Edelsbrunner and Welzl, Emo},
journal = {Journal of Combinatorial Theory Series A},
number = {2},
pages = {159 -- 166},
publisher = {Elsevier},
title = {{On the maximal number of edges of many faces in an arrangement}},
doi = {10.1016/0097-3165(86)90078-6},
volume = {41},
year = {1986},
}
@article{4108,
abstract = {We propose a uniform and general framework for defining and dealing with Voronoi diagrams. In this framework a Voronoi diagram is a partition of a domainD induced by a finite number of real valued functions onD. Valuable insight can be gained when one considers how these real valued functions partitionD ×R. With this view it turns out that the standard Euclidean Voronoi diagram of point sets inR d along with its order-k generalizations are intimately related to certain arrangements of hyperplanes. This fact can be used to obtain new Voronoi diagram algorithms. We also discuss how the formalism of arrangements can be used to solve certain intersection and union problems.},
author = {Herbert Edelsbrunner and Seidel, Raimund},
journal = {Discrete & Computational Geometry},
number = {1},
pages = {25 -- 44},
publisher = {Springer},
title = {{Voronoi diagrams and arrangements}},
doi = {10.1007/BF02187681},
volume = {1},
year = {1986},
}
@article{4110,
abstract = {For $H$ a set of lines in the Euclidean plane, $A(H)$ denotes the induced dissection, called the arrangement of $H$. We define the notion of a belt in $A(H)$, which is bounded by a subset of the edges in $A(H)$, and describe two algorithms for constructing belts. All this is motivated by applications to a host of seemingly unrelated problems including a type of range search and finding the minimum area triangle with the vertices taken from some finite set of points.
© 1986 © Society for Industrial and Applied Mathematics},
author = {Herbert Edelsbrunner and Welzl, Emo},
journal = {SIAM Journal on Computing},
number = {1},
pages = {271 -- 284},
publisher = {SIAM},
title = {{Constructing belts in two-dimensional arrangements with applications}},
doi = {10.1137/0215019},
volume = {15},
year = {1986},
}
@article{4324,
abstract = {The maintenance of polygenic variation through a balance between mutation and stabilizing selection can be approximated in two ways. In the ‘Gaussian’ approximation, a normal distribution of allelic effects is assumed at each locus. In the ‘House of Cards’ approximation, the effect of new mutations is assumed to be large compared with the spread of the existing distribution. These approximations were developed to describe models where alleles may have a continuous range of effects. However, previous analyses of models with only two alleles have predicted an equilibrium variance equal to that given by the ‘House of Cards’ approximation. These analyses of biallelic models have assumed that, at equilibrium, the population mean is at the optimum. Here, it is shown that many stable equilibria may coexist, each giving a slight deviation from the optimum. Though the variance is given by the ‘House of Cards’ approximation when the mean is at the optimum, it increases towards a value of the same order as that given by the ‘Gaussian’ approximation when the mean deviates from the optimum. Thus, the equilibrium variance cannot be predicted by any simple model, but depends on the previous history of the population.},
author = {Nicholas Barton},
journal = {Genetical Research},
number = {3},
pages = {209 -- 216},
publisher = {Cambridge University Press},
title = {{The maintenance of polygenic variation through a balance between mutation and stabilising selection}},
doi = {10.1017/S0016672300023156},
volume = {47},
year = {1986},
}
@article{3579,
author = {Herbert Edelsbrunner and Jaromczyk, Jerzy W},
journal = {Congressus Numerantium},
pages = {193 -- 200},
publisher = {Utilitas Mathemtica Publ. Inc.},
title = {{How often can you see yourself in a convex configuration of mirrors?}},
volume = {53},
year = {1986},
}
@article{3663,
abstract = {The conditional average frequency of rare alleles has been shown in simulations to provide a simple and robust estimator of the number of individuals exchanged between local populations in an island model (Nm). This statistic is defined as the average frequency of an allele in those samples in which the allele is present. Here, we show that the conditional average frequency can be calculated from the distribution of allele frequencies. It is a measure of the spread of this distribution, and so is analogous to the standardised variance, FST. Analytic predictions for the island model of migration agree well with the corresponding simulation results. These predictions are based on the assumption that the rare alleles found in samples have reached a "quasi-equilibrium" distribution. As well as relating the conditional average frequency to the underlying allele frequency distribution, our results provide a more accurate method of estimating Nm from the conditional average frequency of private alleles in samples of different sizes.},
author = {Nicholas Barton and Slatkin, Montgomery},
journal = {Heredity},
number = {3},
pages = {409 -- 416},
publisher = {Nature Publishing Group},
title = {{A quasi-equilibrium theory of the distribution of rare alleles in a subdivided population}},
doi = {10.1038/hdy.1986.63},
volume = {56},
year = {1986},
}