Title
Convex hulls of spheres and convex hulls of disjoint convex polytopes
Abstract
Given a set @S of spheres in E^d, with d=3 and d odd, having a constant number of m distinct radii @r"1,@r"2,...,@r"m, we show that the worst-case combinatorial complexity of the convex hull of @S is @Q(@?"1"="j"==3 odd, where n"i spheres have radius @r"i, i=1,2, and @r"2@r"1, such that their convex hull has combinatorial complexity @W(n"1n"2^@?^d^2^@?+n"2n"1^@?^d^2^@?). Our construction is then generalized to the case where the spheres have m=3 distinct radii. For the upper bound, we reduce the sphere convex hull problem to the problem of computing the worst-case combinatorial complexity of the convex hull of a set of m disjoint d-dimensional convex polytopes in E^d^+^1, where d=3 odd, a problem which is of independent interest. More precisely, we show that the worst-case combinatorial complexity of the convex hull of a set of m disjoint d-dimensional convex polytopes in E^d^+^1 is O(@?"1"="j"==3. Finally, we discuss how to compute convex hulls of spheres with a constant number of distinct radii, or convex hulls of a constant number of disjoint convex polytopes.
Year
DOI
Venue
2013
10.1016/j.comgeo.2013.02.001
Comput. Geom.
Keywords
Field
DocType
worst-case combinatorial complexity,convex hull,combinatorial complexity,independent interest,distinct radius,constant number,i sphere,m distinct radius,sphere convex hull problem,disjoint convex polytopes,spheres,combinatorial geometry,discrete geometry
Orthogonal convex hull,Discrete mathematics,Combinatorics,Convex body,Convex combination,Convex set,Convex hull,Subderivative,Convex polytope,Mathematics,Convex analysis
Journal
Volume
Issue
ISSN
46
6
0925-7721
Citations 
PageRank 
References 
1
0.36
22
Authors
3
Name
Order
Citations
PageRank
Menelaos I. Karavelas122918.99
Raimund Seidel2606.03
Eleni Tzanaki3246.72