Abstract
In this paper we study lower bounds and approximation algorithms for the independence number α(G) in k-clique-free graphs G. Ajtai et al. [1] showed that there exists an absolute constant c 1 such that for any k-clique-free graph G on n vertices and with average degree ¯d, α(G) ≥ c 1 log((log ¯d)/k)/d n
We improve this lower bound for α(G) as follows: Let G be a connected k-clique-free graph on n vertices with maximum degree δ(G) ≤ n − 2. Then α(G) ≥ n(¯d(k − 2)2 log(¯d(k − 2)2) − ¯d(k − 2)2 + 1)/(¯d(k − 2)2 − 1)2 for ¯d ≥ 2.
For graphs with moderate maximum degree Halldórsson and J. Radhakrishnan
For graphs with moderate to large values of δ Halldórsson and J. Radhakrishnan
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© 1998 Springer-Verlag Berlin Heidelberg
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Schiermeyer, I. (1998). Approximating maximum independent set in k-clique-free graphs. In: Jansen, K., Rolim, J. (eds) Approximation Algorithms for Combinatiorial Optimization. APPROX 1998. Lecture Notes in Computer Science, vol 1444. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0053972
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DOI: https://doi.org/10.1007/BFb0053972
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