Let G be a planar graph with n vertices, v be a specified vertex of G, and P be a set of n points in the Euclidian plane ~2 in general position. A straight-line embeddin9 of G onto P is an embedding of G onto R 2 whose images of vertices are distinct points in P and whose images of edges are (straig
On the intersection of edges of a geometric graph by straight lines
โ Scribed by N. Alon; M.A. Perles
- Publisher
- Elsevier Science
- Year
- 1986
- Tongue
- English
- Weight
- 969 KB
- Volume
- 60
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
โฆ Synopsis
A geometric graph ( = gg) is a pair G = (V, E), where V is a finite set of points ( = vertices) in general position in the plane, and E is a set of open straight line segments ( = edges) whose endpoints are in V. G is a convex gg ( = egg) if V is the set of vertices of a convex polygon. For n 3 1, 0 se c (;) and m Z= 1 let )) be the maximal number such that for every gg (egg) G with n vertices and e edges there exists a set of m lines whose union intersects at least 2 (I,) edges of G. In this paper we determine Z,(n, e, m) precisely for all admissible n, e and m and show that Z(n, e, m) = Z,(n, e, m) if 2me > n2 and in many other cases.
๐ SIMILAR VOLUMES
Wiseman, J.A., On the intersection rank of a graph, Discrete Mathematics 104 293-305.
We prove that every connected graph on n vertices can be covered by at most nร2+O(n 3ร4 ) paths. This implies that a weak version of a well-known conjecture of Gallai is asymptotically true.