Let F be a family of n convex sets in the plane. A set of light sources S illuminates F if every point on the boundary of each element of F is visible from at least one element in S. We prove that if F is a family of n line segments, n >/11, then [-2n/3 7 light sources are always sufficient to illum
Reconstructing sets of orthogonal line segments in the plane
β Scribed by Franz Rendl; Gerhard Woeginger
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 550 KB
- Volume
- 119
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
Rend], F. and G. Woeginger, Reconstructing sets of orthogonal line segments in the plane, Discrete Mathematics 119 (1993) 1677174.
We show that reconstructing a set of n orthogonal line segments in the plane from the set of their vertices can be done in O(n log n) time, if the segments are allowed to cross. If the segments are not allowed to cross, the problem becomes NP-complete.
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Let n k denote the number of times the kth largest distance occurs among a set S of n points. We show that if S is the set of vertices of a convex polygone in the euclidean plane, then n1+2n2~3n and n2<~n +n 1. Together with the well-known inequality n~<~n and the trivial inequalities n~>~O and n2>~