A four-dimensional cousin of the Segre cubic

• Laurent Manivel ^[1]
  1. [1] Université de Toulouse

     Université de Toulouse

     Arrondissement de Toulouse, Francia

     
• Localización: Revista matemática iberoamericana, ISSN 0213-2230, Vol. 40, Nº 3, 2024, págs. 1089-1114
• Idioma: inglés
• DOI: 10.4171/RMI/1448
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• Resumen

  • This note is devoted to a special Fano fourfold defined by a four-dimensional space of skew-symmetric forms in five variables. This fourfold appears to be closely related with the classical Segre cubic and its Cremona–Richmond configuration of planes. Among other exceptional properties, it is infinitesimally rigid and has Picard number six. We show how to construct it by blow-up and contraction, starting from a configuration of five planes in a four-dimensional quadric, compatibly with the symmetry group S5. From this construction, we are able to describe the Chow ring explicitly.