Interpolation by Weak Chebyshev Spaces Original Research Article

We present two characterizations of Lagrange interpolation sets for weak Chebyshev spaces. The first of them is valid for an arbitrary weak Chebyshev space U and is based on an analysis of the structure of zero sets of functions in U extending Stockenbergʹs theorem. The second one holds for all weak Chebyshev spaces that possess a locally linearly independent basis.