Common Spectral Properties of Bounded Right Linear Operators AC and BA in the Quaternionic Setting

Abstract

Let X be a two-sided quaternionic Banach space and let \(A, B, C: X \longrightarrow X\) be bounded right linear quaternionic operators such that \(ACA=ABA\). Let q be a non-zero quaternion. In this paper, we investigate the common properties of \((AC)^{2}-2Re(q)AC+|q|^2I\) and \((BA)^{2}-2Re(q)BA+|q|^2I\) where I stands for the identity operator on X. In particular, we show that

$$\begin{aligned} \sigma ^{S}_{{\mathcal {F}}}(AC)\backslash \{0\} = \sigma ^{S}_{{\mathcal {F}}}(BA)\backslash \{0\} \end{aligned}$$

where \(\sigma ^{S}_{{\mathcal {F}}}(.)\) is a distinguished part of the spherical spectrum.