Displaying similar documents to “On The Frequency With Which Bounded Functions Have Spectral Gaps”

On the spectral Nevanlinna-Pick problem

Constantin Costara (2005)

Studia Mathematica

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We give several characterizations of the symmetrized n-disc Gₙ which generalize to the case n ≥ 3 the characterizations of the symmetrized bidisc that were used in order to solve the two-point spectral Nevanlinna-Pick problem in ℳ ₂(ℂ). Using these characterizations of the symmetrized n-disc, which give necessary and sufficient conditions for an element to belong to Gₙ, we obtain necessary conditions of interpolation for the general spectral Nevanlinna-Pick problem. They also allow us...

Spectral subspaces for the Fourier algebra

K. Parthasarathy, R. Prakash (2007)

Colloquium Mathematicae

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In this note we define and explore, à la Godement, spectral subspaces of Banach space representations of the Fourier-Eymard algebra of a (nonabelian) locally compact group.

Analytic joint spectral radius in a solvable Lie algebra of operators

Daniel Beltiţă (2001)

Studia Mathematica

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We introduce the concept of analytic spectral radius for a family of operators indexed by some finite measure space. This spectral radius is compared with the algebraic and geometric spectral radii when the operators belong to some finite-dimensional solvable Lie algebra. We describe several situations when the three spectral radii coincide. These results extend well known facts concerning commuting n-tuples of operators.