Title
The (p,q)-total labeling problem for trees
Abstract
A (p,q)-total labeling of a graph G is an assignment f from the vertex set V(G) and the edge set E(G) to the set of nonnegative integers such that |f(x)-f(y)|=p if x is a vertex and y is an edge incident to x, and |f(x)-f(y)|=q if x and y are a pair of adjacent vertices or a pair of adjacent edges, for all x and y in V(G)@?E(G). A k-(p,q)-total labeling is a (p,q)-total labeling f:V(G)@?E(G)-{0,...,k}, and the (p,q)-total labeling problem asks the minimum k, which we denote by @l\"p\",\"q^T(G), among all possible assignments. In this paper, we first give new upper and lower bounds on @l\"p\",\"q^T(G) for some classes of graphs G, in particular, tight bounds on @l\"p\",\"q^T(T) for trees T. We then show that if p@?3q/2, the problem for trees T is linearly solvable, and completely determine @l\"p\",\"q^T(T) for trees T with @D=4, where @D is the maximum degree of T. It is contrasting to the fact that the L(p,q)-labeling problem, which is a generalization of the (p,q)-total labeling problem, is NP-hard for any two positive integers p and q such that q is not a divisor of p.
Year
DOI
Venue
2012
10.1016/j.disc.2012.01.007
ISAAC
Keywords
DocType
Volume
tree
Journal
312
Issue
ISSN
Citations 
8
0012-365X
1
PageRank 
References 
Authors
0.36
18
4
Name
Order
Citations
PageRank
Toru Hasunuma114216.00
Toshimasa Ishii211017.03
Hirotaka Ono340056.98
yushi uno422228.80