On Fuglede's conjecture and the existence of universal spectra

Bálint Farkas, Máté Matolcsi, Péter Móra

Recent methods developed by Tao \cite{tao}, Kolountzakis and Matolcsi \cite{nspec} have led to counterexamples to Fugelde's Spectral Set Conjecture in both directions. Namely, in $…