Deformation Classification of Real Non-singular Cubic Threefolds with a Marked Line

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FİNASHİN S., Kharlamov V.

Arnold Mathematical Journal, vol.4, no.3-4, pp.345-414, 2018 (Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 4 Issue: 3-4
  • Publication Date: 2018
  • Doi Number: 10.1007/s40598-019-00096-w
  • Journal Name: Arnold Mathematical Journal
  • Journal Indexes: Scopus
  • Page Numbers: pp.345-414
  • Keywords: Fano surfaces of real lines, Monodromy, Real cubic threefolds, Real deformation classification, Real plane quintics, Real theta-characteristics
  • Middle East Technical University Affiliated: Yes


© 2019, Institute for Mathematical Sciences (IMS), Stony Brook University, NY. We prove that the space of pairs (X, l) formed by a real non-singular cubic hypersurface X⊂ P 4 with a real line l⊂ X has 18 connected components and give for them several quite explicit interpretations. The first one relates these components to the orbits of the monodromy action on the set of connected components of the Fano surface F R (X) formed by real lines on X. For another interpretation we associate with each of the 18 components a well defined real deformation class of real non-singular plane quintic curves and show that this deformation class together with the real deformation class of X characterizes completely the component.