Siciak's homogeneous extremal functions, holomorphic extension and a generalization of Helgason's support theorem

Jöran Bergh, Ragnar Sigurdsson

We prove that a function, which is defined on a union of lines $\mathbb{C}E$ through the origin in ${\mathbb{C}}^n$ with direction vectors in $E\subset {\mathbb{C}}^n$ and is holomorp…