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We consider the problem of augmenting an $n$-vertex tree with one shortcut in order to minimize the diameter of the resulting graph. The tree is embedded in an unknown space and we have access to an oracle that, when queried on a pair of…

Data Structures and Algorithms · Computer Science 2018-10-03 Davide Bilò

Let $P$ be a path graph of $n$ vertices embedded in a metric space. We consider the problem of adding a new edge to $P$ such that the diameter of the resulting graph is minimized. Previously (in ICALP 2015) the problem was solved in…

Data Structures and Algorithms · Computer Science 2016-08-17 Haitao Wang

Given a set $\mathcal{P}$ of $h$ pairwise disjoint simple polygonal obstacles in $\mathbb{R}^2$ defined with $n$ vertices, we compute a sketch $\Omega$ of $\mathcal{P}$ whose size is independent of $n$, depending only on $h$ and the input…

Computational Geometry · Computer Science 2019-09-17 R Inkulu , Sanjiv Kapoor

Given two points in a simple polygon $P$ of $n$ vertices, its geodesic distance is the length of the shortest path that connects them among all paths that stay within $P$. The geodesic center of $P$ is the unique point in $P$ that minimizes…

Computational Geometry · Computer Science 2015-01-06 Hee-Kap Ahn , Luis Barba , Prosenjit Bose , Jean-Lou de Carufel , Matias Korman , Eunjin Oh

Enclosing depth is a recently introduced depth measure which gives a lower bound to many depth measures studied in the literature. So far, enclosing depth has only been studied from a combinatorial perspective. In this work, we give the…

Computational Geometry · Computer Science 2024-02-20 Bernd Gärtner , Fatime Rasiti , Patrick Schnider

Most existing distance metric learning methods assume perfect side information that is usually given in pairwise or triplet constraints. Instead, in many real-world applications, the constraints are derived from side information, such as…

Machine Learning · Computer Science 2012-03-19 Kaizhu Huang , Rong Jin , Zenglin Xu , Cheng-Lin Liu

It is known that every closed curve of length \leq 4 in R^n (n>0) can be surrounded by a sphere of radius 1, and that this is the best bound. Letting S denote the circle of circumference 4, with the arc-length metric, we here express this…

Metric Geometry · Mathematics 2021-10-15 George M. Bergman

The paper provides bounds for the ropelength of a link in terms of the crossing numbers of its split components. As in earlier papers, the bounds grow with the square of the crossing number; however, the constant involved is a substantial…

Geometric Topology · Mathematics 2007-05-23 Jason Cantarella , X. W. Faber , Chad A. Mullikin

Acceleration of algorithms is becoming a crucial problem, if larger data sets are to be processed. Evaluation of algorithms is mostly done by using computational geometry approach and evaluation of computational complexity. However in…

Computational Geometry · Computer Science 2022-08-29 Vaclav Skala

Given a set of pairwise disjoint polygonal obstacles in the plane, finding an obstacle-avoiding Euclidean shortest path between two points is a classical problem in computational geometry and has been studied extensively. The previous best…

Computational Geometry · Computer Science 2021-06-01 Haitao Wang

For many shape analysis problems in computer vision and scientific imaging (e.g., computational anatomy, morphological cytometry), the ability to align two closed curves in the plane is crucial. In this paper, we concentrate on rigidly…

Differential Geometry · Mathematics 2025-01-30 Günay Dogan , Javier Bernal , Charles Hagwood

This paper gives simple distributed algorithms for the fundamental problem of computing graph distances in the Congested Clique model. One of the main components of our algorithms is fast matrix multiplication, for which we show an…

Distributed, Parallel, and Cluster Computing · Computer Science 2015-03-24 Keren Censor-Hillel , Ami Paz

We introduce space-efficient plane-sweep algorithms for basic planar geometric problems. It is assumed that the input is in a read-only array of $n$ items and that the available workspace is $\Theta(s)$ bits, where $\lg n \leq s \leq n…

Data Structures and Algorithms · Computer Science 2016-04-25 Amr Elmasry , Frank Kammer

Cutwidth is one of the classic layout parameters for graphs. It measures how well one can order the vertices of a graph in a linear manner, so that the maximum number of edges between any prefix and its complement suffix is minimized. As…

Data Structures and Algorithms · Computer Science 2017-02-16 Archontia C. Giannopoulou , Michał Pilipczuk , Jean-Florent Raymond , Dimitrios M. Thilikos , Marcin Wrochna

We present an optimal O*(n^2) time algorithm for deciding if a metric space (X,d) on n points can be isometrically embedded into the plane endowed with the l_1-metric. It improves the O*(n^2 log^2 n) time algorithm of J. Edmonds (2008).…

Computational Geometry · Computer Science 2011-07-08 Nicolas Catusse , Victor Chepoi , Yann Vaxès

The ropelength of a knot is the minimum length required to tie it. Computational upper bounds have previously been computed for every prime knot with up to 11 crossings. Here, we present ropelength measurements for the 2176 knots with 12…

Geometric Topology · Mathematics 2023-06-01 Alexander R. Klotz , Caleb J. Anderson

We study the shortcut Fr\'{e}chet distance, a natural variant of the Fr\'{e}chet distance, that allows us to take shortcuts from and to any point along one of the curves. The classic Fr\'echet distance is a bottle-neck distance measure and…

Computational Geometry · Computer Science 2013-12-05 Maike Buchin , Anne Driemel , Bettina Speckmann

Tightness is a generalisation of the notion of convexity: a space is tight if and only if it is "as convex as possible", given its topological constraints. For a simplicial complex, deciding tightness has a straightforward exponential time…

Computational Geometry · Computer Science 2018-10-24 Bhaskar Bagchi , Benjamin A. Burton , Basudeb Datta , Nitin Singh , Jonathan Spreer

A fundamental problem in computational geometry is to compute an obstacle-avoiding Euclidean shortest path between two points in the plane. The case of this problem on polygonal obstacles is well studied. In this paper, we consider the…

Computational Geometry · Computer Science 2015-04-28 Danny Z. Chen , Haitao Wang

Given a sequence of integers, we want to find a longest increasing subsequence of the sequence. It is known that this problem can be solved in $O(n \log n)$ time and space. Our goal in this paper is to reduce the space consumption while…

Data Structures and Algorithms · Computer Science 2017-12-27 Masashi Kiyomi , Hirotaka Ono , Yota Otachi , Pascal Schweitzer , Jun Tarui