Multivariate spline bases, oriented matroids and zonotopal tilings
In the first part of this work, we uncover a connection between polynomial-reproducing bases of simplex splines and certain single-element liftings of oriented matroids associated to point configurations. We use this correspondence to construct a broad family of spline bases on generic point multisets, generalizing a known result on Delaunay configurations. Our spline bases are naturally defined on finite knot sets with affine dependencies and higher multiplicities, without need for special treatment of degenerate cases. We reformulate our bases in the language of zonotopal tilings, via the Bohne-Dress theorem, obtaining a link to a known construction algorithm for bivariate spline bases based on centroid triangulations. In the second part of this work, we restrict again our attention to weighted Delaunay configurations and the associated spline bases, and we capitalize on our combinatorial viewpoint to extend, in this restricted case, the well-known bivariate construction algorithm to higher dimensions and generic point multisets. Finally, we employ this machinery to propose algorithms for the determination and evaluation of all multivariate basis spline functions supported on a given point.
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