When is the image of a convex set under a holomorphic function convex?

268 Views Asked by At

I have a holomorphic function on a domain $G$ containing a compact, convex set $K$. Clearly, if $K$ is a line segment, then $f(K)$ might be an arc on a circle and therefore not convex. But what if the interior of $K$ is non-empty? Is it then true that $f(K)$ is convex?

1

There are 1 best solutions below

2
On

No. The map $z \mapsto z^2$ sends rectangles to nonconvex curvilinear quadrilaterals with parabolic arcs.

enter image description here