7
$\begingroup$

Let $A$ be a C$^*$-algebra. I have seen theorems either stating or implying that if $A$ is the algebra of bounded linear operators on a separable Hilbert space (Herrero et al.), or the Calkin algebra, or an AF-C$^*$-algebra (Skoufranis), then every quasi-nilpotent element in $A$ is a norm-limit of nilpotent elements. Is the general case known: is every quasi-nilpotent element in a C$^*$-algebra a norm-limit of nilpotent elements?

$\endgroup$

0

You must log in to answer this question.

Browse other questions tagged .