A discrete Fourier analysis on the dodecahedron is studied, from which results on a tetrahedron is deduced by invariance. The results include Fourier analysis in trigonometric functions, interpolation and cubature formulas on these domains. In particular, a trigonometric Lagrange interpolation on the tetrahedron is shown to satisfy an explicit compact formula and the Lebesgue constant of the in...

In this paper, we propose a modified Lagrange type interpolation operator to approximate functions in Sobolev spaces by continuous piecewise polynomials. In order to define interpolators for "rough" functions and to preserve piecewise polynomial boundary conditions, the approximated functions are averaged appropriately either on dor (d 1 )-simplices to generate nodal values for the interpolatio...

We give a simple, geometric and explicit construction of bivariate interpolation at certain points in a square (called Padua points), giving compact formulas for their fundamental Lagrange polynomials. We show that the associated norms of the interpolation operator, i.e., the Lebesgue constants, have minimal order of growth of O((log n)2). To the best of our knowledge this is the first complete...

We investigate weighted Lp(0 < p <.) convergence of Hermite and Hermite– Fejér interpolation polynomials of higher order at the zeros of Freud orthogonal polynomials on the real line. Our results cover as special cases Lagrange, Hermite– Fejér and Krylov–Stayermann interpolation polynomials. © 2001 Academic Press

A trivariate Lagrange interpolation method based on C cubic splines is described. The splines are defined over a special refinement of the Freudenthal partition of a cube partition. The interpolating splines are uniquely determined by data values, but no derivatives are needed. The interpolation method is local and stable, provides optimal order approximation, and has linear complexity.

A trivariate Lagrange interpolation method based on C1 cubic splines is described. The splines are defined over a special refinement of the Freudenthal partition of a cube partition. The interpolating splines are uniquely determined by data values, but no derivatives are needed. The interpolation method is local and stable, provides optimal order approximation, and has linear complexity.

Let {St} be a sequence of interpolation schemes in Rn of degree d (i.e. for each St one has unique interpolation by a polynomial of total degree ≤ d) and total order ≤ l. Suppose that the points of St tend to 0 ∈ Rn as t→ ∞ and the Lagrange-Hermite interpolants, HSt , satisfy limt→∞HSt(x) = 0 for all monomials xα with |α| = d + 1. Theorem: limt→∞HSt (f) = T d(f) for all functions f of class Cl−...

and the formulas may be used to extend the definition of Si(w, ¿) and S2(n, k) for arbitrary real n. In a previous paper [2] the writer has proved several apparently new formulas relating the two kinds of Stirling numbers to each other. Carlitz [l] has generalized these results in part as follows. Instead of considering the polynomial B['\ let fk(z) denote an arbitrary polynomial in z of degree...

Quadrature convergence of the extended Lagrange interpolant L2n+1f for any continuous function f is studied, where the interpolation nodes are the n zeros τi of an orthogonal polynomial of degree n and the n+ 1 zeros τ̂j of the corresponding “induced” orthogonal polynomial of degree n + 1. It is found that, unlike convergence in the mean, quadrature convergence does hold for all four Chebyshev w...

Let {pm(wα)}m be the sequence of the polynomials orthonormal w.r.t. the Sonin-Markov weight wα(x) = e−x 2 |x|. The authors study extended Lagrange interpolation processes essentially based on the zeros of pm(wα)pm+1(wα), determining the conditions under which the Lebesgue constants, in some weighted uniform spaces, are optimal.