“…The question goes back to Whitney [35], [36], [37], with contri-butions by Glaeser [22], Brudnyi-Shvartsman [5]- [10] and [29], [30], [31], Zobin [38], [39], Bierstone-Milman-Paw lucki [2], [3], Fefferman [13]- [19] and A. and Y. Brudnyi [4]. Here, we take E finite, and we pose the question from the viewpoint of theoretical computer science.…”