Skew symmetry of a class of operators

Abstract

An operator $T$ on a complex Hilbert space $\mathcal{H}$ is said to be skew symmetric if there exists a conjugate-linear, isometric involution $C:\mathcal{H}\rightarrow\mathcal{H}$ such that $CTC=-T^*$. In this paper, using an interpolation theorem related to conjugations, we give a geometric characterization for a class of operators to be skew symmetric. As an application, we get a description of skew symmetric partial isometries.