Minkowski product of convex sets and product numerical range

Chi-Kwong Li, Diane Christine Pelejo, Yiu-Tung Poon +1

Let $K_1,K_2$ be two compact convex sets in $C$. Their Minkowski product is the set $K_1{K}_2=\{ab:a\in K_1,b\in K_2\}$. We show that the set $K_1{K}_2$ is star-shaped i…