Let \(f\colon \mathbb{Z}^d\to \mathbb{C}\). The divergence of \(f\) is defined by
\[ \div f(x) := (\partial_1 f(x), \ldots , \partial_d f(x)). \]
\[
\DeclareMathOperator{\div}{div}
\]
Let \(f\colon \mathbb{Z}^d\to \mathbb{C}\). The divergence of \(f\) is defined by
\[ \div f(x) := (\partial_1 f(x), \ldots , \partial_d f(x)). \]