Abstract
For integers p ≥ q, a L(p, q)-labeling of a network G is an integer labeling of the nodes of G such that adjacent nodes receive integers which differ by at least p, and nodes at distance two receive labels which differ by at least q. The minimum number of labels required in such labeling is λ p q (G). This arises in the context of frequency channel assignment in mobile and wireless networks and often G is planar. We show that if G is planar then \( \lambda _q^p (G) \leqslant \tfrac{5} {3}(2q - 1)\Delta + 12p + 144q - 78 \). We also provide an O(n 2) time algorithm to find such a labeling. This provides a \( (\tfrac{5} {3} + o(1)) \)-approximation algorithm for the interesting case of q = 1, improving the best previous approximation ratio of 2.
A full version of this paper is available with title “A Bound on the Chromatic Number of the Square of a Planar Graph” at http://www.cs.toronto.edu/~mreza/research.html
Supported by NSERC, a Sloan Research Fellowship, and a Premier’s Research Excellence Award.
Supported by Research Assistantship, Department of computer science, and University open fellowship, University of Toronto.
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Molloy, M., Salavatipour, M.R. (2002). Frequency Channel Assignment on Planar Networks. In: Möhring, R., Raman, R. (eds) Algorithms — ESA 2002. ESA 2002. Lecture Notes in Computer Science, vol 2461. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-45749-6_64
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DOI: https://doi.org/10.1007/3-540-45749-6_64
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