We compute the supports of the perverse cohomology sheaves of the Hitchin fibration for GLn{\mathrm{GL}_{n}} over the locus of reduced spectral curves. In contrast to the case of meromorphic Higgs fields we find additional supports at the loci of reducible spectral curves. Their contribution to the global cohomology is governed by a finite twist of Hitchin fibrations for Levi subgroups. The corresponding summands give non-trivial contributions to the cohomology of the moduli spaces for every n≥2{n\geq{2}}. A key ingredient is a restriction result for intersection cohomology sheaves that allows us to compare the fibration to the one defined over versal deformations of spectral curves.
De Cataldo M.A.A., Heinloth J., Migliorini L. (2021). A support theorem for\break the Hitchin fibration: The case of GLnand KC. JOURNAL FÜR DIE REINE UND ANGEWANDTE MATHEMATIK, 2021(780), 41-77 [10.1515/crelle-2021-0045].
A support theorem for\break the Hitchin fibration: The case of GLnand KC
Migliorini L.
2021
Abstract
We compute the supports of the perverse cohomology sheaves of the Hitchin fibration for GLn{\mathrm{GL}_{n}} over the locus of reduced spectral curves. In contrast to the case of meromorphic Higgs fields we find additional supports at the loci of reducible spectral curves. Their contribution to the global cohomology is governed by a finite twist of Hitchin fibrations for Levi subgroups. The corresponding summands give non-trivial contributions to the cohomology of the moduli spaces for every n≥2{n\geq{2}}. A key ingredient is a restriction result for intersection cohomology sheaves that allows us to compare the fibration to the one defined over versal deformations of spectral curves.File | Dimensione | Formato | |
---|---|---|---|
10.1515_crelle-2021-0045 (1).pdf
accesso aperto
Tipo:
Versione (PDF) editoriale
Licenza:
Licenza per accesso libero gratuito
Dimensione
586.55 kB
Formato
Adobe PDF
|
586.55 kB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.