PreprintCC BY 4.0arXiv
Derivatives of Theta Functions and a Problem of Lyubarskii and Nes
Abstract
We characterize all lattices Λ⊂ ℝ2 of rational density for which the Gabor system generated by the first Hermite function along Λ is a frame for L2(ℝ). We prove that these are precisely the lattices whose density satisfies $D(Λ) = \frac{q}{p} $ where p,q ∈ ℕ are coprime with q ≥ p+2, thereby confirming a conjecture of Lyubarskii and Nes. A formalization of our main result in Lean $4$ is also included.
Related
- Congruences modulo powers of 5 and 7 for the crank and rank parity functions and related mock theta-functions
- Theta functions after Weil
- Bicolored Eulerian quasisymmetric functions, affine lengths, and Theta operators
- On the occurrence of congruence multiplicities between Ramanujan's theta functions
- Hypothetical connection of the theta functions of Dirichlet characters with the real cyclotomic fields
BibTeX
@misc{liehr2026derivatives,
title = {{Derivatives of Theta Functions and a Problem of Lyubarskii and Nes}},
author = {Lukas Liehr and Irina Shafkulovska and Mitchell A. Taylor},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.27846},
eprint = {2609.27846},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.27846},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Derivatives of Theta Functions and a Problem of Lyubarskii and Nes
AU - Lukas Liehr
AU - Irina Shafkulovska
AU - Mitchell A. Taylor
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.27846
UR - https://arxiv.org/abs/2609.27846
AB - We characterize all lattices Λ⊂ ℝ^2 of rational density for which the Gabor system generated by the first Hermite function along Λ is a frame for L^2(ℝ). We prove that these are precisely the lattices whose density satisfies $D(Λ) = \frac{q}{p} $ where p,q ∈ ℕ are coprime with q ≥ p+2, thereby confirming a conjecture of Lyubarskii and Nes. A formalization of our main result in Lean $4$ is also included.
ER -