Fixed-Copy Exponent Sets and Strict Singularity of Composition Operators Between Hardy Spaces

Yecheng Shi, Songxiao Li

For a bounded operator \(T\) between Banach spaces, we introduce the \emph{fixed-copy exponent sets} \[ \begin{aligned} \operatorname{Fix}_{\ell}(T) &:= \{r\ge1:T\text{ fixes a cop…