The average distance Β΅(G) of a connected graph G of order n is the average of the distances between all pairs of vertices of G, i.e., Β΅(G) = ( n 2 ) -1 {x,y}βV (G) d G (x, y), where V (G) denotes the vertex set of G and d G (x, y) is the distance between x and y. We prove that every connected graph
NP-completeness and degree restricted spanning trees
β Scribed by Robert James Douglas
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 449 KB
- Volume
- 105
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
In this paper several results are proved: (1) Deciding whether a given planar graph G with maximum degree 3 has a spanning tree T, where deg(x, T) = 1 or 3 for each node x, is NP-Complete.
(2) For each proper subset S of the positive integers Z+ with 1 E S and (S( 2 2, deciding whether a planar graph G = (V, E) has a spanning tree T such that deg(x, T) E S, for all x E V, is NP-Complete.
(3) For each non-empty proper subset S of Z*, deciding whether, given a planar graph G = (V, E) and integer N with 1 s N < IVI, there is a spanning tree T for G such that T has at least [at most] N nodes x with deg(x, T) ES is NP-complete.
Also, as corollaries of (1)) we show that for a planar graph G , with n nodes and maximum degree 3, it is NP-complete to decide (4) if there is a spanning tree with at least [exactly] n/2 + 1 leaves and (5) if G has a connected dominating set with cardinality <n/2 -1.
π SIMILAR VOLUMES
## Abstract The __k__ βDegree constrained Minimum Spanning Tree Problem (__k__ βDMSTP) consists in finding a minimal cost spanning tree satisfying the condition that every node has a degree no greater than a fixed value __k__. Here we consider an extension where besides the edge costs, a concave co