Abstract
We study generalizations of convex hulls to polygonal domains with holes. Convexity in Euclidean space is based on the notion of shortest paths, which are straight-line segments. In a polygonal domain, shortest paths are polygonal paths called geodesics. One possible generalization of convex hulls is based on the “rubber band” conception of the convex hull boundary as a shortest curve that encloses a given set of sites. However, it is NP-hard to compute such a curve in a general polygonal domain. Hence, we focus on a di erent, more direct generalization of convexity, where a set X is geodesically convex if it contains all geodesics between every pair of points x, y ∈ X. The corresponding geodesic convex hull presents a few surprises, and turns out to behave quite di erently compared to the classic Euclidean setting or to the geodesic hull inside a simple polygon. We describe a class of geometric objects that su ce to represent geodesic convex hulls of sets of sites, and characterize which such domains are geodesically convex. Using such a representation we present an algorithm to construct the geodesic convex hull of a set of O(n) sites in a polygonal domain with a total of n vertices and h holes in O(n3h3+ε) time, for any constant ε > 0.
Originalsprache | englisch |
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Titel | 16th Scandinavian Symposium and Workshops on Algorithm Theory, SWAT 2018 |
Herausgeber (Verlag) | Schloss Dagstuhl - Leibniz-Zentrum für Informatik |
Seiten | 81-813 |
Seitenumfang | 733 |
Band | 101 |
ISBN (elektronisch) | 9783959770682 |
DOIs | |
Publikationsstatus | Veröffentlicht - 1 Juni 2018 |
Extern publiziert | Ja |
Veranstaltung | 16th Scandinavian Symposium and Workshops on Algorithm Theory, SWAT 2018 - Malmo, Schweden Dauer: 18 Juni 2018 → 20 Juni 2018 |
Konferenz
Konferenz | 16th Scandinavian Symposium and Workshops on Algorithm Theory, SWAT 2018 |
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Land/Gebiet | Schweden |
Ort | Malmo |
Zeitraum | 18/06/18 → 20/06/18 |
ASJC Scopus subject areas
- Software