Independence numbers of graphs and generators of ideals


This article investigates the generators of certain homogeneous ideals which are associated with graphs with bounded independence numbers. These ideals first appeared in the theory oft-designs. The main theorem suggests a new approach to the Clique Problem which isNP-complete. This theorem has a more general form in commutative algebra dealing with ideals associated with unions of linear varieties. This general theorem is stated in the article; a corollary to it generalizes Turán’s theorem on the maximum graphs with a prescribed clique number.

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    R. L. Graham, S.-Y. Li andW.-C. W. Li, On the structure oft-designs,S.I.A.M. J. Alg. Disc. Meth. 1 (1980) 8–14.

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    P. Turán, On the theory of graphs,Coll. Math. 3 (1954) 19–30.

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Research supported in part by NSF Grant MCS77-03533.

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Li, SY.R., Li, WC.W. Independence numbers of graphs and generators of ideals. Combinatorica 1, 55–61 (1981).

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AMS subject classification (1980)

  • 05 C 35
  • 13 A 15, 05 C 15