Rigid local systems with monodromy group the Conway group C o 2

Nicholas M. Katz, Antonio Rojas-León, Pham Huu Tiep

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We first develop some basic facts about hypergeometric sheaves on the multiplicative group m in characteristic p > 0. Certain of their Kummer pullbacks extend to irreducible local systems on the affine line in characteristic p > 0. One of these, of rank 23 in characteristic p = 3, turns out to have the Conway group Co2, in its irreducible orthogonal representation of degree 23, as its arithmetic and geometric monodromy groups.

Original languageEnglish (US)
Pages (from-to)341-360
Number of pages20
JournalInternational Journal of Number Theory
Issue number2
StatePublished - Mar 1 2020


All Science Journal Classification (ASJC) codes

  • Algebra and Number Theory


  • Rigid local systems
  • monodromy groups
  • sporadic simple groups

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