Displaying similar documents to “Operators of Bochner-Riesz type for the helix”

Multipliers for Hermite expansions.

Sundaram Thangavelu (1987)

Revista Matemática Iberoamericana

Similarity:

The aim of this paper is to prove certain multiplier theorems for the Hermite series.

Spectral localization, power boundedness and invariant subspaces under Ritt's type condition

Yu. Lyubich (1999)

Studia Mathematica

Similarity:

For a bounded linear operator T in a Banach space the Ritt resolvent condition ∥ R λ ( T ) ∥ ≤ C / | λ - 1 | (|λ| > 1) can be extended (changing the constant C) to any sector |arg(λ - 1)| ≤ π - δ, a r c c o s ( C - 1 ) < δ < π / 2 . This implies the power boundedness of the operator T. A key result is that the spectrum σ(T) is contained in a special convex closed domain. A generalized Ritt condition leads to a similar localization result and then to a theorem on invariant subspaces.

Rough maximal functions and rough singular integral operators applied to integrable radial functions.

Peter Sjögren, Fernando Soria (1997)

Revista Matemática Iberoamericana

Similarity:

Let Ω be homogeneous of degree 0 in R and integrable on the unit sphere. A rough maximal operator is obtained by inserting a factor Ω in the definition of the ordinary maximal function. Rough singular integral operators are given by principal value kernels Ω(y) / |y|, provided that the mean value of Ω vanishes. In an earlier paper, the authors showed that a two-dimensional rough maximal operator is of weak type (1,1) when restricted to radial functions. This result is now extended to...