Title
The (2,1)-total labeling number of outerplanar graphs is at most Δ + 2
Abstract
A (2, 1)-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 {0, 1, ..., k} of nonnegative integers such that |f(x) - f(y)| ≥ 2 if x is a vertex and y is an edge incident to x, and |f(x) - f(y)| ≥ 1 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). The (2, 1)-total labeling number λ2T(G) of G is defined as the minimum k among all possible assignments. In [D. Chen and W. Wang. (2,1)-Total labelling of outerplanar graphs. Discr. Appl. Math. 155 (2007)], it was conjectured that all outerplanar graphs G satisfy λ2T(G) ≤ Δ(G)+2, where Δ(G) is the maximum degree of G, while they also showed that it is true for G with Δ(G) ≥ 5. In this paper, we solve their conjecture completely, by proving that λ2T(G) ≤ Δ(G)+2 even in the case of Δ(G) ≤ 4.
Year
DOI
Venue
2010
10.1007/978-3-642-19222-7_11
IWOCA
Keywords
Field
DocType
maximum degree,adjacent vertex,total labelling,outerplanar graph,adjacent edge,edge set e,minimum k,graph g,edge incident,w. wang,satisfiability
Integer,Discrete mathematics,Graph,Combinatorics,Bound graph,Vertex (geometry),Degree (graph theory),Conjecture,Mathematics
Conference
Citations 
PageRank 
References 
2
0.36
10
Authors
4
Name
Order
Citations
PageRank
Toru Hasunuma114216.00
Toshimasa Ishii211017.03
Hirotaka Ono340056.98
yushi uno422228.80