JournalsrmiVol. 28, No. 1pp. 297–304

Some examples of CC^\infty extension by linear operators

  • Charles Fefferman

    Princeton University, United States
  • Fulvio Ricci

    Scuola Normale Superiore, Pisa, Italy
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For two kinds of sets XX in Rn\mathbb{R}^n, we prove the existence of linear continuous operators extending CC^\infty functions on XX to CC^\infty functions on Rn\mathbb{R}^n. 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).

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Charles Fefferman, Fulvio Ricci, Some examples of CC^\infty extension by linear operators. Rev. Mat. Iberoam. 28 (2012), no. 1, pp. 297–304

DOI 10.4171/RMI/678