A hidden set is a set of points such that no two points in the set are visible to each other. In this paper we study hidden sets of points in arrangements of segments, and we provide bounds for its maximum size that are optimal up to a factor 2.
Point location in zones of k-flats in arrangements
โ Scribed by Mark de Berg; Marc van Kreveld; Otfried Schwarzkopf; Jack Snoeyink
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 885 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0925-7721
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โฆ Synopsis
Let A(H) be the arrangement of a set H of n hyperplanes in d-space. A k-flat is a k-dimensional affine subspace of d-space. The zone of a k-flat f with respect to H is the set of all faces in A(H) that intersect f. In this paper we study some problems on zones of k-flats. Our most important result is a data structure for point location in the zone of a k-flat. This structure uses O(n [a/2j+E + n k+~) preprocessing time and space and has a query time of O(log 2 n). We also show how to test efficiently whether two flats are visible from each other with respect to a set of hyperplanes. Then point location in m faces in arrangements is studied. Our data structure for this problem has size O(n[d/2J+eT~ [d/zl/d) and the query time is O(log 2 n).
๐ SIMILAR VOLUMES
The locations of optimal stress points in Lagrangian and serendipity elements are determined by using the symbolic mathematical tool MATHEMATICA # . It is found that, for the Lagrange family of elements of order more than two, the co-ordinates of optimal stress points slightly dier from those of the