Paramodular forms in CAP representations of ${\rm GSp}(4)$
Volume 194 / 2020
Acta Arithmetica 194 (2020), 319-340
MSC: 11F46, 11F70.
DOI: 10.4064/aa180606-23-9
Published online: 1 April 2020
Abstract
We explicitly determine the non-tempered local Arthur packets for ${\rm GSp} (4)$ of Howe–Piatetski-Shapiro type, Saito–Kurokawa type and Soudry type. As a consequence we show that Gritsenko lifts are the only paramodular forms that can occur in global CAP representations of ${\rm GSp} (4,\mathbb A _{\mathbb Q} )$.