Fuglede's conjecture holds in $\mathbb{Q}_p$
arXiv:1512.08904
Abstract
Fuglede's conjecture in $\mathbb{Q}_p$ is proved. That is to say, a Borel set of positive and finite Haar measure in $\mathbb{Q}_p$ is a spectral set if and only if it tiles $\mathbb{Q}_p$ by translation.
24 pages