The $n/d$-conjecture for central indecomposable hyperplane arrangements

Let $f_\mathscr{A}$ define a central reduced indecomposable arrangement of $d$ hyperplanes in $\mathbb{C}^n$. The $n/d$-conjecture. The number $-n/d$ is a root of the Bernstein--Sato polynomial of $f_\mathscr{A}$. This conjecture concerns the occurrence of a specific root of the Bernstein--Sato polynomial for central indecomposable arrangements; the source proves it for broader classes under additional hypotheses, including arrangements for which the differential annihilator is generated by derivations.