Resonance equals reducibility forA-hypergeometric systems
Mathias Schulze, Uli Walther · Algebra & Number Theory · 2012
Classical theorems of Gel'fand et al. and recent results of Beukers show that nonconfluent Cohen-Macaulay A-hypergeometric systems have reducible monodromy representation if and only if the continuous parameter is A-resonant.We remove both the confluence and Cohen-Macaulayness conditions while simplifying the proof.