L(2,1)-labeling of the strong product of paths and cycles.
An L(2,1)-labeling of a graph G = (V, E) is a function f from the vertex set V(G) to the set of nonnegative integers such that the labels on adjacent vertices differ by at least two and the labels on vertices at distance two differ by at least one. The span of f is the difference between the largest and the smallest numbers in f(V). The λ-number of G, denoted by λ(G), is the minimum span over all L(2,1)-labelings of G. We consider the λ-number of Pn⊠C m and for n ≤ 11 the λ-number of Cn⊠Cm. We determine λ-numbers of graphs of interest with the exception of a finite number of graphs and we improve the bounds on the λ-number of Cn⊠Cm, m ≥ 24 and n ≥ 26.
School of Information Science and Technology, Chengdu University, Chengdu 610106, China ; Key Laboratory of Pattern Recognition and Intelligent Information Processing, Institutions of Higher Education of Sichuan Province, Sichuan 610106, China.
Zehui
0000-0003-0764-4135
Z
Shao
Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška Cesta 160, 2000 Maribor, Slovenia.
Aleksander
0000-0003-3705-0071
A
Vesel
D000465:Algorithms; D008962:Models, Theoretical