Abstract:
Let $T$ be a contraction on a Banach space, and let $A_{T}$ ($W_{T}$) be the closure in the uniform (respectively, in the weak) operator topology of the set of all polynomials in $T$. The asymptotic behavior of the radicals of the algebras $A_{T}$ and $W_{T}$ is studied.
Keywords:Banach space, contraction, spectrum, local spectrum, radical.