A lower bound on the norm of interpolation with an extended Tchebycheff system
For a class of spaces spanned by extended Chebyshev systems defined on a closed interval, the norm of interpolation into a space of dimension \(n+1\) must strictly exceed the norm of optimal Lagrange interpolation into the space of polynomials of degree n-1. As shown by some examples, this fact raises some new questions.
scientific article; zbMATH DE number 3966965