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The Arthur-Packet Support Equality for Real Reductive Groups
Abstract
Let ψ be a real Arthur parameter and let ψ2 be the unipotent parameter in a fixed Jordan decomposition. Adams, Ionov, Mason-Brown, and Vogan proved that the microlocal packet of ψ is contained in the support of the two-step Jordan induction of the packet of ψ2, and conjectured equality. We prove the reverse inclusion. The argument first passes to a sufficiently positive translate, where the relevant connected components of the ABV spaces have a common flag-variety model. Perverse devissage reduces the problem to a singular-support implication, which follows from the incidence calculation underlying the AIMV microstalk comparison. Coherent continuation for individual packet members then returns the result to the original parameter.
Related
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- Effective results in representation theory of reductive groups over local fields
BibTeX
@misc{yang2026arthurpacket,
title = {{The Arthur-Packet Support Equality for Real Reductive Groups}},
author = {Jiawei Yang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.19197},
eprint = {2609.19197},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.19197},
}
RIS
TY - UNPB
TI - The Arthur-Packet Support Equality for Real Reductive Groups
AU - Jiawei Yang
PY - 2026
DA - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2609.19197
UR - https://arxiv.org/abs/2609.19197
AB - Let ψ be a real Arthur parameter and let ψ_2 be the unipotent parameter in a fixed Jordan decomposition. Adams, Ionov, Mason-Brown, and Vogan proved that the microlocal packet of ψ is contained in the support of the two-step Jordan induction of the packet of ψ_2, and conjectured equality. We prove the reverse inclusion. The argument first passes to a sufficiently positive translate, where the relevant connected components of the ABV spaces have a common flag-variety model. Perverse devissage reduces the problem to a singular-support implication, which follows from the incidence calculation underlying the AIMV microstalk comparison. Coherent continuation for individual packet members then returns the result to the original parameter.
ER -