منابع مشابه
A Transformation Which Preserves the Clique Number
We introduce a graph transformation which preserves the clique number. When applied to graphs containing no odd hole and no cricket (a particular graph on 5 vertices) the transformation also preserves the chromatic number. Using this transformation we derive a polynomial algorithm for the computation of the clique number of all graphs in a class which strictly contains diamond-free graphs. Furt...
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We derive from Boolean methods a transformation which, when applicable, builds from a given graph a new graph with the same stability number and with the number of vertices decreased by one. We next describe classes of graphs for which such a transformation leads to a polynomial algorithm for computing the stability number.
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Explicit substitutions were proposed by Abadi, Cardelli, Curien, Hardin and LLvy to internalise substitutions into-calculus and to propose a mechanism for computing on substitutions. is another view of the same concept which aims to explain the process of substitution and to decompose it in small steps. is simple and preserves strong normalisation. Apparently that important property cannot stay...
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We specialize Schmüdgen’s Positivstellensatz and its Putinar and Jacobi and Prestel refinement, to the case of a polynomial f ∈ R[X, Y ] + R[Y, Z], positive on a compact basic semi-algebraic set K described by polynomials in R[X, Y ] and R[Y, Z] only, or in R[X] and R[Y, Z] only (i.e. K is cartesian product). In particular, we show that the preordering P (g, h) (resp. quadratic module Q(g, h)) ...
متن کاملIndependence number and clique minors
Since χ(G) · α(G) ≥ |V (G)|, Hadwiger’s Conjecture implies that any graph G has the complete graph Kdn α e as a minor, where n is the number of vertices of G and α is the maximum number of independent vertices in G. Motivated by this fact, it is shown that any graph on n vertices with independence number α ≥ 3 has the complete graph Kd n 2α−2 e as a minor. This improves the well-known theorem o...
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ژورنال
عنوان ژورنال: Journal of Combinatorial Theory, Series B
سال: 2001
ISSN: 0095-8956
DOI: 10.1006/jctb.2001.2061