Suzuki-Trotter expansion

$e^{A+B}={\lim }_{n\to \infty }{\left(e^{\frac{A}{n}}{e}^{\frac{B}{n}}\right)}^n$. This is a key result used for Trotterization. Not to be confused with the Suzuki-Trotter formula $e^{A+B}\approx e^{\frac{A}{2}}{e}^B{e}^{\frac{A}{2}}$, used to reduce errors to $\mathcal{O}(t^3)$.