Characteristic functions and -orthogonality properties of Chebyshev polynomials of third and fourth kind.
Characterization of best harmonic and superharmonic L1-approximations.
Characterization of compact subsets of algebraic varieties in terms of Bernstein type inequalities
We show that in the class of compact sets K in with an analytic parametrization of order m, the sets with Zariski dimension m are exactly those which admit a Bernstein (or a van der Corput-Schaake) type inequality for tangential derivatives of (the traces of) polynomials on K.
Characterization of optimal polynomial and rational starting approximations
Characterization of saturation classes in
Characterization of smooth, compact algebraic curves in ℝ²
Characterization of the smoothness of functions with a given order of approximation by polynomials on the real line
Characterization of the Speed of Convergence of the Trapezoidal Rule.
Characterization theorem's of Hermite polynomials.
Characterizations of elements of best approximation in non-Archimedean normed spaces
Characterizations of -predual spaces by centerable subsets
In this note, we prove that a real or complex Banach space is an -predual space if and only if every four-point subset of is centerable. The real case sharpens Rao’s result in [Chebyshev centers and centerable sets, Proc. Amer. Math. Soc. 130 (2002), no. 9, 2593–2598] and the complex case is closely related to the characterizations of -predual spaces by Lima [Complex Banach spaces whose duals are -spaces, Israel J. Math. 24 (1976), no. 1, 59–72].
Characterizations of periodic function spaces of Besov-Sobolev type via approximation processes and relations to the strong summability of Fourier series
Characterizations of random approximations
Some characterizations of random approximations are obtained in a locally convex space through duality theory.
Chebychev Sets which are not Suns.
Chebyshev Approximation by Spline Functions with Free Knots.
Chebyshev approximation via polynomial mappings and the convergence behaviour of Krylov subspace methods.
Chebyshev centers, E-Chebyshev centers and the Hausdorff metric.
Chebyshev centers in hyperplanes of
We give a full characterization of the closed one-codimensional subspaces of , in which every bounded set has a Chebyshev center. It turns out that one can consider equivalently only finite sets (even only three-point sets) in our case, but not in general. Such hyperplanes are exactly those which are either proximinal or norm-one complemented.
Chebyshev Centres in Normed Spaces
Chebyshev coficients for L1-preduals and for spaces with the extension property.
We apply the Chebyshev coefficients λf and λb, recently introduced by the authors, to obtain some results related to certain geometric properties of Banach spaces. We prove that a real normed space E is an L1-predual if and only if λf(E) = 1/2, and that if a (real or complex) normed space E is a P1 space, then λb(E) equals λb(K), where K is the ground field of E.