S. Meda

  1. Endpoint estimates for first-order Riesz transforms associated to the Ornstein-Uhlenbeck operator.

    Authors: G. Mauceri, S. Meda, P. Sjögren
    Subjects: Functional Analysis
    Abstract

    In the setting of Euclidean space with the Gaussian measure g, we consider
    all first-order Riesz transforms associated to the infinitesimal generator of
    the Ornstein-Uhlenbeck semigroup. These operators are known to be bounded on
    L^p(g), for 1<p<\infty. We determine which of them are bounded from H^1(g) to
    L^1(g) and from L^\infty(g) to BMO(g). Here H^1(g) and BMO(g) are the spaces
    introduced in this setting by the first two authors. Surprisingly, we find that
    the results depend on the dimension of the ambient space.

  2. Atomic decomposition of Hardy type spaces on certain noncompact manifolds.

    Authors: G. Mauceri, S. Meda, M. Vallarino
    Subjects: Functional Analysis
    Abstract

    In this paper we consider a complete connected noncompact Riemannian manifold
    M with bounded geometry and spectral gap. We prove that the Hardy type spaces
    X^k(M), introduced in a previous paper of the authors, have an atomic
    characterization. As an application, we prove that the Riesz transforms of even
    order 2k are bounded from X^k(M) to L^1(M)and on L^p(M) for 1<p<\infty.

  3. Equivalence of norms on finite linear combinations of atoms.

    Authors: G. Mauceri, S. Meda
    Subjects: Functional Analysis
    Abstract

    Let M be a space of homogeneous type and denote by F^\infty_{cont}(M) the
    space of finite linear combinations of continuous (1,\infty)-atoms. In this
    note we give a simple function theoretic proof of the equivalence on
    F^\infty_{cont}(M) of the H^1-norm and the norm defined in terms of finite
    linear combinations of atoms. The result holds also for the class of
    nondoubling metric measure spaces considered in previous works of A. Carbonaro
    and the authors.

Syndicate content