Weak separability and partial Fermi isospectrality of discrete periodic Schrödinger operators

Jifeng Chu, Kang Lyu, Chuan-Fu Yang

In this paper, we consider the discrete periodic Schrödinger operators $\Delta +V$ on ${\mathbb{Z}}^d$, where $V$ is $\Gamma$-periodic with $Γ=q_1 \mathbb{Z}\oplus q_2\mathbb{Z}\oplus\cdots\oplus q_d\m…