Joint spectrum shrinking maps on projections

Wenhua Qian, Dandan Xiao, Tanghong Tao +2

Let $\mathcal{H}$ be a finite dimensional complex Hilbert space with dimension $n\ge 3$ and $\mathcal{P}(\mathcal{H})$ the set of projections on $\mathcal{H}$. Let $φ: \mathcal P(\mat…