Marcelino Ibañez

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Univariate spline discrete quasi-interpolants (abbr. dQIs) are approximation operators using B-spline expansions with coefficients which are linear combinations of discrete values of the function to be approximated. When working with nonuniform partitions, the main challenge is to find dQIs which have both good approximation orders and bounded uniform norms(More)
Spline quasi-interpolants with best approximation orders and small norms are useful in several applications. In this paper, we construct the so-called near-best discrete and integral quasi-interpolants based on H-splines, i.e., B-splines with regular hexagonal supports on the uniform three-directional mesh of the plane. These quasi-interpolants are obtained(More)
We prove that if a matroid M contains two disjoint bases (or, dually, if its ground set is the union of two bases), then T M (a, a) ≤ max{T M (2a, 0), T M (0, 2a)} for a ≥ 2. This resembles the conjecture that appears in C. Merino and D. (0, 2)} for matroids which contains two disjoint bases or its ground set is the union of two bases. We also prove the(More)
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