Newstead's Mayer-Vietoris argument in characteristic 2

Christopher Scaduto, Matthew Stoffregen

Research output: Contribution to journalArticlepeer-review


Consider the moduli space of framed flat U(2) connections with fixed odd determinant over a surface. Newstead combined some fundamental facts about this moduli space with the Mayer-Vietoris sequence to compute its betti numbers over any field not of characteristic 2. We adapt his method in characteristic 2 to produce conjectural recursive formulae for the mod two betti numbers of the framed moduli space which we partially verify. We also discuss the interplay with the mod two cohomology ring structure of the unframed moduli space.

Original languageEnglish (US)
Article number1950065
JournalInternational Journal of Mathematics
Issue number12
StatePublished - Nov 1 2019
Externally publishedYes


  • flat connection
  • mod 2 cohomology
  • Stable bundle

ASJC Scopus subject areas

  • Mathematics(all)


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