For two kinds of sets in , we prove the existence of linear continuous operators extending functions on to functions on . The sets we consider are: (a) sequences of points in the real line converging to 0 at a polynomial rate, (b) flag-shaped sets in the plane, which are unions of half-lines with slopes as in (a).
Cite this article
Charles Fefferman, Fulvio Ricci, Some examples of extension by linear operators. Rev. Mat. Iberoam. 28 (2012), no. 1, pp. 297–304