Fresh Examples of Hyponormal Terraced Matrices with Transcendental Entries

Abstract

This note calls attention to an alternative version of the main result from [4], which can be used together with Maclaurin series expansions and trigonometric identities to show that the terraced matrices generated by the sequences $\{\ln (1+1/(n+1)) : n \geq 0\}$, $\{\tan (1/(n+2)) : n \geq 0\}$, and $\{\sinh (1/(n+2)) : n \geq 0\}$ are hyponormal operators on $\ell^2$. Along the way it is also shown that the matrix generated by $\{\tan (1/(n+1)) : n \geq 0\}$ is not a hyponormal operator on $\ell^2$.