Approximation by ridge function fields over compact sets

We study the approximation of a continuous function field over a compact set T , by a continuous field of ridge approximants over T , named ridge function fields. We first give general density results about function fields, and show how they apply to ridge function fields. We next discuss the parametrization of sets of ridge function fields, and give additional density results for some class of continuous ridge function fields, that admits a weak-parametrization. Finally, we discuss the construction of the elements in that class. Index Terms — Ridge approximation, nonlinear approximation, function field, density.