|
ABSTRACT
For any set X of points (in any dimension) and any k &equil; 1,2, ..., we introduce the concept of the k-hull of X. This unifies the well-known notion of 'convex hulls' with the notion of 'centers' recently introduced by F.F. Yao. The concept is intimately related to some other concepts (k-belts, k-sets) studied by Edelsbrunner, Welzl, Lovász, Erdös and others. Several computational problems related to k-hulls are studied here. Some of our algorithms are of interest in themselves because of the techniques employed; in particular, the 'parametric' searching technique of Megiddo is used in a nontrivial way. We will also extend Megiddo's technique to Las Vegas algorithms. Our results have applications to a variety of problems in computational geometry: efficient computation of the 'cut' guaranteed by the classical 'Ham Sandwich theorem', faster preprocessing time for polygon retrieval, and theoretical improvements to a problem of intersecting lines and points posed by Hopcroft.
REFERENCES
Note: OCR errors may be found in this Reference List extracted from the full text article. ACM has opted to expose the complete List rather than only correct and linked references.
| |
1
|
M. K. Agoston, Algebraic Topology, Marcel Dekker, New York, 1976.
|
| |
2
|
|
 |
3
|
|
| |
4
|
B. Chazelle, "Optimal algorithms for computing depths and layers", Brown University Technical Report No. CS-83-13, March 1983.
|
| |
5
|
R. Cole and C. K. Yap, "A parallel median algorithm", preliminary version, September 1983.
|
| |
6
|
D. Dobkin and H. Edelsbrunner, private communication.
|
| |
7
|
L. Dubins and E. Spanier, "How to cut a cake fairly", AMM, 68(1961), 1-17.
|
| |
8
|
H. Edelsbrunner and E. Welzl, "On the number of line-separations of a finite set in the plane", to appear, J. Comb. Theory, A.
|
| |
9
|
H. Edelsbrunner and E. Welzl, "Halfplanar Range Estimation", Report F98, Inst. for Inf. Proc., Tech. Univ. of Graz, Austria (1982).
|
| |
10
|
H. Edelsbrunner and E. Welzl, "Halfplanar range search in linear space and O(n0.695) query time", Report F111, Inst. for Inf. Proc., Tech. Univ. of Graz, Austria (1983).
|
| |
11
|
P. Erdös, L. Lovász, A. Simmons and E. G. Straus, "Dissection Graphs of Planar Point Sets", in A Survey of Combinatorial Theory, J. N. Srivastava et al, eds., North-Holland, 1973, 139-149.
|
| |
12
|
T. P. Hill, "Determining a fair border", AMM 90:7(1983)438-442.
|
| |
13
|
L. Lovász, "On the number of halving lines", Ann. Univ. Sci. Budapest, Eötvos Sect. Mat. 14, 1971, 107-108.
|
 |
14
|
|
| |
15
|
D. Muller and F. Preparata, Finding the intersection of two convex polyhedra, Theoretical Computer Science, 7(1979), 217-236.
|
| |
16
|
M. H. Overmars and J. van Leeuwen, "Maintenance of configurations in the plane", JCSS, 23(1981), 166-204.
|
| |
17
|
F. Preparata, New Parallel Sorting Schemes, IEEE Trans. Comput., C-27(1978),pp.669-673.
|
| |
18
|
L. Valiant, "Parallelism in Comparison Problems", SIAM J. Comp., Vol.4, No.3, 1975, 348-355.
|
| |
19
|
D. Willard, "Polygon Retrieval", SIAM J. Comp. 11, 1982, 149-165.
|
| |
20
|
I. M. Yaglom and V. G. Boltyanskii, Convex Figures, (trans.) Holt, Rinehart and Winston, 1961.
|
 |
21
|
|
|