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We study the crossing-minimization problem in a layered graph drawing of planar-embedded rooted trees whose leaves have a given total order on the first layer, which adheres to the embedding of each individual tree. The task is then to…

Discrete Mathematics · Computer Science 2024-02-29 Julia Katheder , Stephen G. Kobourov , Axel Kuckuk , Maximilian Pfister , Johannes Zink

$\renewcommand{\Re}{{\rm I\!\hspace{-0.025em} R}} \newcommand{\SetX}{\mathsf{X}} \newcommand{\VorX}[1]{\mathcal{V} \pth{#1}} \newcommand{\Polygon}{\mathsf{P}} \newcommand{\Space}{\overline{\mathsf{m}}}…

Computational Geometry · Computer Science 2015-12-01 Sariel Har-Peled

A convex polygon $Q$ is inscribed in a convex polygon $P$ if every side of $P$ contains at least one vertex of $Q$. We present algorithms for finding a minimum area and a minimum perimeter convex polygon inscribed in any given convex…

Metric Geometry · Mathematics 2021-09-24 Csenge Lili Ködmön , Zsolt Lángi

We present an $O(nrG)$ time algorithm for computing and maintaining a minimum length shortest watchman tour that sees a simple polygon under monotone visibility in direction $\theta$, while $\theta$ varies in $[0,180^{\circ})$, obtaining…

Computational Geometry · Computer Science 2023-04-25 Bengt J. Nilsson , David Orden , Leonidas Palios , Carlos Seara , Paweł Żyliński

Two kinds of approximation algorithms exist for the k-BALANCED PARTITIONING problem: those that are fast but compute unsatisfying approximation ratios, and those that guarantee high quality ratios but are slow. In this paper we prove that…

Computational Complexity · Computer Science 2019-04-29 Andreas Emil Feldmann

Polygons are cycles embedded into the plane; their vertices are associated with $x$- and $y$-coordinates and the edges are straight lines. Here, we consider a set of polygons with pairwise non-overlapping interior that may touch along their…

Computational Geometry · Computer Science 2024-09-23 Carsten R. Seemann , Peter F. Stadler , Marc Hellmuth

We prove that it is NP-hard to dissect one simple orthogonal polygon into another using a given number of pieces, as is approximating the fewest pieces to within a factor of $1+1/1080-\varepsilon$.

Computational Geometry · Computer Science 2015-12-22 Jeffrey Bosboom , Erik D. Demaine , Martin L. Demaine , Jayson Lynch , Pasin Manurangsi , Mikhail Rudoy , Anak Yodpinyanee

We give a counterexample to a conjecture of Poon [Poo06] that any orthogonal tree in two dimensions can always be flattened by a continuous motion that preserves edge lengths and avoids self-intersection. We show our example is locked by…

Computational Geometry · Computer Science 2008-01-30 David Charlton , Erik D. Demaine , Martin L. Demaine , Gregory Price , Yaa-Lirng Tu

This paper investigated the problem of embedding a simple Hamiltonian Cycle with n vertices on n points inside a simple polygon. This problem seeks to embed a straight-line cycle (without bends), which does not intersect either itself or…

Computational Geometry · Computer Science 2022-08-22 Maryam Fadavian , Heidar Fadavian

Detecting polygons defined by a set of line segments in a plane is an important step in analyzing vector drawings. This paper presents an approach combining several algorithms to detect basic polygons from arbitrary line segments. The…

Computational Geometry · Computer Science 2023-12-29 Alfredo Ferreira , Manuel J. Fonseca , Joaquim A. Jorge

An $\alpha$-thin tree $T$ of a graph $G$ is a spanning tree such that every cut of $G$ has at most an $\alpha$ proportion of its edges in $T$. The Thin Tree Conjecture proposes that there exists a function $f$ such that for any $\alpha >…

Computational Complexity · Computer Science 2026-01-01 Alice Moayyedi

Minimum Bisection denotes the NP-hard problem to partition the vertex set of a graph into two sets of equal sizes while minimizing the width of the bisection, which is defined as the number of edges between these two sets. We first consider…

Combinatorics · Mathematics 2017-08-23 Cristina G. Fernandes , Tina Janne Schmidt , Anusch Taraz

Motivated by the $k$-center problem in location analysis, we consider the \emph{polygon burning} (PB) problem: Given a polygonal domain $P$ with $h$ holes and $n$ vertices, find a set $S$ of $k$ vertices of $P$ that minimizes the maximum…

Computational Geometry · Computer Science 2021-11-18 William Evans , Rebecca Lin

Art Gallery is a fundamental visibility problem in Computational Geometry. The input consists of a simple polygon P, (possibly infinite) sets G and C of points within P, and an integer k; the task is to decide if at most k guards can be…

Computational Geometry · Computer Science 2020-03-18 Akanksha Agrawal , Kristine V. K. Knudsen , Daniel Lokshtanov , Saket Saurabh , Meirav Zehavi

In the convex covering problem, we are given a convex polygon with holes $P$ and the goal is to cover $P$ using a small number of convex polygons that lie inside $P$. In this paper, we solve the problem using the following strategy. We find…

Computational Geometry · Computer Science 2025-06-23 Guilherme D. da Fonseca

We will consider some extensions of the polygonal art gallery problem. In a recent paper Morrison has shown the smallest (9 sides) example of an art gallery that cannot be observed by guards placed in every third corner. Author also…

Computational Geometry · Computer Science 2019-09-20 Eryk Lipka

An O(n) test for polygon convexity is stated and proved. It is also proved that the test is minimal in a certain exact sense.

Computational Geometry · Computer Science 2007-05-23 Iosif Pinelis

We study the NP-complete Minimum Shared Edges (MSE) problem. Given an undirected graph, a source and a sink vertex, and two integers p and k, the question is whether there are p paths in the graph connecting the source with the sink and…

Computational Complexity · Computer Science 2016-02-05 Till Fluschnik , Stefan Kratsch , Rolf Niedermeier , Manuel Sorge

We consider the watchman route problem for multiple watchmen in staircase polygons, which are rectilinear $x$- and $y$-monotone polygons. For two watchmen, we propose an algorithm to find an optimal solution that takes quadratic time,…

Computational Geometry · Computer Science 2025-07-03 Anna Brötzner , Bengt J. Nilsson , Christiane Schmidt

Given a polygonal curve P, a pointset S, and an \epsilon > 0, we study the problem of finding a polygonal curve Q whose vertices are from S and has a Frechet distance less or equal to \epsilon to curve P. In this problem, Q must visit every…

Computational Geometry · Computer Science 2012-11-20 Anil Maheshwari , Jörg-Rüdiger Sack , Kaveh Shahbaz
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