• openAccess   Smooth and Polyhedral Norms via Fundamental Biorthogonal Systems 

      Dantas, Sheldon; Hájek, Petr; Russo, Tommaso Oxford University Press (2022-08-04)
      Let X be a Banach space with a fundamental biorthogonal system, and let Y be the dense subspace spanned by the vectors of the system. We prove that Y admits a C∞-smooth norm that locally depends on finitely many coordinates ...