Fuglede's conjecture on cyclic groups of order $p^n q$
Discrete analysis (2017)
Cet article a éte moissonné depuis la source Scholastica
We show that the spectral set conjecture by Fuglede holds in the setting of cyclic groups of order $p^n q$, where $p$, $q$ are distinct primes and $n\geq1$. This means that a subset $E$ of such a group $G$ tiles the group by translation ($G$ can be partitioned into translates of $E$) if and only if there exists an orthogonal basis of $L^2(E)$ consisting of group characters. The main ingredient of the present proof is the structure of vanishing sums of roots of unity of order $N$, where $N$ has at most two prime divisors; the extension of this proof to the case of cyclic groups of order $p^n q^m$ seems therefore feasible. The only previously known infinite family of cyclic groups, for which Fuglede's conjecture is verified in both directions, is that of cyclic $p$-groups, i.e. $\mathbb{Z}_{p^n}$.
@article{DAS_2017_a8,
author = {Romanos-Diogenes Malikiosis and Mihail N. Kolountzakis},
title = {Fuglede's conjecture on cyclic groups of order $p^n q$},
journal = {Discrete analysis},
year = {2017},
language = {en},
url = {http://geodesic.mathdoc.fr/item/DAS_2017_a8/}
}
Romanos-Diogenes Malikiosis; Mihail N. Kolountzakis. Fuglede's conjecture on cyclic groups of order $p^n q$. Discrete analysis (2017). http://geodesic.mathdoc.fr/item/DAS_2017_a8/