منابع مشابه
Lower Bounds on Stabbing Lines in 3-space
A stabbing line for a set of convex polyhedra is extremal if it passes through four edges and is tangent to the polyhedra containing those edges. In this paper we present three constructions of convex polyhedra with many extremal lines. The rst construction shows (n 2) extremal stabbing lines constrained to meet two skew lines. The second shows (n 4) extremal lines which are tangent to two poly...
متن کاملOn stabbing triangles by lines in 3-space
We give an example of a set P of 3n points in R3 such that, for any partition of P into triples, there exists a line stabbing Ω( √ n) of the triangles determined by the triples.
متن کاملLower Bounds for Line Stabbing
We present an (n log n) xed order algebraic decision tree lower bound for determining the existence of a line stabber for a family of n line segments in the plane. We give the same lower bound for determining the existence of a line stabber for n translates of a circle in the plane. In proving this lower bound, we show that this problem is equivalent to determining if the width of a set of poin...
متن کاملStabbing Orthogonal Objects in 3-Space
David M. Mount Fan-Tao Pu Department of Computer Science University of Maryland College Park, MD 20742 fmount,[email protected] 1 Motivation Computer graphics is the source of many interesting and challenging applications for the design of geometric algorithms and data structures. Applications in global illumination simulation and radiosity [7] have motivated our study of problems involving line...
متن کاملFixed-parameter tractability and lower bounds for stabbing problems
We study the following general stabbing problem from a parameterized complexity point of view: Given a set S of n translates of an object in R, find a set of k lines with the property that every object in S is ”stabbed” (intersected) by at least one line. We show that when S consists of axis-parallel unit squares in R the (decision) problem of stabbing S with axis-parallel lines is W[1]-hard wi...
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ژورنال
عنوان ژورنال: Computational Geometry
سال: 1993
ISSN: 0925-7721
DOI: 10.1016/0925-7721(93)90030-a