Article de recherche - Géométrie algébrique
Simplicity of Tangent bundles on the moduli spaces of symplectic and orthogonal bundles over a curve
[Simplicité des fibrés tangents des espaces de modules des fibrés symplectiques et orthogonaux sur une courbe]
Comptes Rendus. Mathématique, Tome 362 (2024) no. G5, pp. 493-510

The variety of minimal rational tangents associated to Hecke curves was used by J.-M. Hwang [8] to prove the simplicity of the tangent bundle on the moduli of vector bundles over a curve. In this paper, we use the tangent maps of the symplectic and orthogonal Hecke curves to prove an analogous result for symplectic and orthogonal bundles. In particular, we show the nondegeneracy of the associated variety of minimal rational tangents, which implies the simplicity of the tangent bundle on the moduli spaces of symplectic and orthogonal bundles over a curve. We also show that for large enough genus, the tangent map is an embedding for a general symplectic or orthogonal bundle.

La variété des tangentes des courbes minimales rationnelles associés aux courbes de Hecke, a été utilisée par J.-M. Hwang [8] pour prouver la simplicité du fibré tangent à l’espace de modules des fibrés vectoriels sur une courbe. Nous utilisons les applications tangentes des courbes de Hecke symplectiques et orthogonales pour démontrer un résultat analogue pour les fibrés symplectiques et orthogonaux. En particulier, nous prouvons que la variété des tangentes aux courbes rationnelles minimales associée est non dégénérée ; ce qui implique la simplicité des fibrés tangents aux espaces de modules des fibrés symplectiques et orthogonaux sur une courbe. Nous montrons d’ailleurs, pour genre suffisamment grand, que l’application tangente est un plongement pour un fibré symplectique ou orthogonal générique.

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DOI : 10.5802/crmath.560
Classification : 14D20, 53C10
Keywords: symplectic bundle, orthogonal bundle, minimal rational tangents

Choe, Insong  1   ; H. Hitching, George  2   ; Hong, Jaehyun  3

1 Department of Mathematics, Konkuk University, 1 Hwayang-dong, Gwangjin-Gu, Seoul 143-701, Republic of Korea
2 Oslo Metropolitan University, Postboks 4, St. Olavs plass, 0130 Oslo, Norway
3 Center for Complex Geometry, Institute for Basic Science (IBS), Daejeon 34126, Republic of Korea
Licence : CC-BY 4.0
Droits d'auteur : Les auteurs conservent leurs droits
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     title = {Simplicity of {Tangent} bundles on the moduli spaces of symplectic and orthogonal bundles over a curve},
     journal = {Comptes Rendus. Math\'ematique},
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Choe, Insong; H. Hitching, George; Hong, Jaehyun. Simplicity of Tangent bundles on the moduli spaces of symplectic and orthogonal bundles over a curve. Comptes Rendus. Mathématique, Tome 362 (2024) no. G5, pp. 493-510. doi: 10.5802/crmath.560

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