Multivariable versions of a lemma of Kaluza's

Stefan Richter, Jesse Sautel

Let $d\in \mathbb{N}$ and $f(z)={\sum }_{\alpha \in {\mathbb{N}}_0^d}{c}_{\alpha }{z}^{\alpha }$ be a convergent multivariable power series in $z=(z_1,\dots ,z_d)$. In this paper we present two conditions on th…