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Variation of local systems and parabolic cohomology

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Abstract

Given a family of local systems on a punctured Riemann sphere, with moving singularities, its first parabolic cohomology is a local system on the base space. We study this situation from different points of view. For instance, we derive universal formulas for the monodromy of the resulting local system. We use a particular example of our construction to prove that the simple groups PSL2(p 2) admit regular realizations over the field ℚ(t) for primesp≢ 1, 4, 16 mod 21.

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Authors and Affiliations

  1. IWR, Universität Heidelberg, INF 368, 69120, Heidelberg, Germany

    Michael Dettweiler

  2. Mathematisches Institut, Universität Bonn, Beringstr. 1, 53115, Bonn, Germany

    Stefan Wewers

Authors
  1. Michael Dettweiler
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  2. Stefan Wewers
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Dettweiler, M., Wewers, S. Variation of local systems and parabolic cohomology. Isr. J. Math. 156, 157–185 (2006). https://doi.org/10.1007/BF02773830

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  • DOI: https://doi.org/10.1007/BF02773830

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