Type: Article
Publication Date: 2018-01-01
Citations: 4
DOI: https://doi.org/10.1137/17m1154187
We show that for every $\ell>1$, there is a counterexample to the $\ell$-modular secrecy function conjecture by Oggier, Solé, and Belfiore [IEEE Trans. Inform. Theory, 62 (2016), pp. 5690--5708]. These counterexamples all satisfy the modified conjecture by Ernvall-Hytönen and Sethuraman [IEEE Trans. Inform. Theory, 62 (2016), pp. 4514--4522]. Furthermore, we provide a method to prove or disprove the modified conjecture for any given $\ell$-modular lattice rationally equivalent to a suitable amount of copies of $\mathbb{Z}\oplus \sqrt{\ell}\,\mathbb{Z}$ with $\ell \in \{3,5,7,11,23\}$. We also provide a variant of the method for strongly $\ell$-modular lattices when $\ell\in \{6,14,15\}$.