Fuglede's conjecture holds on ${\mathbb{Z}}_p^2\times {\mathbb{Z}}_q$

The study of Fuglede’s conjecture on the direct product of elementary abelian groups was initiated by Iosevich et al. For the product of two elementary abelian groups the conjecture holds. For ${\mathbb{Z}}_p^3$ the problem is still open if $p\ge 11$. In connection we prove that Fuglede’s conjecture holds on ${\mathbb{Z}}_p^2\times {\mathbb{Z}}_q$ by developing a method based on ideas from discrete geometry.