Crystalline aspects of geography of low dimensional varieties I: numerology

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This is a modest attempt to study, in a systematic manner, the structure of low dimensional varieties in positive characteristics using p-adic invariants. The main objects of interest in this paper are surfaces and threefolds. There are many results we prove in this paper and not all can be listed in this abstract. Here are some of the results. We prove inequalities related to the Bogomolov–Miyaoka–Yau inequality: in Corollary 4.7 that c126max(5c2+6b1,6c2) holds for a large class of surfaces of general type. In Theorem 4.17 we prove that for a smooth, projective, Hodge–Witt, minimal surface of general type (with additional assumptions such as slopes of Frobenius on Hcris2(X) are >1/2) that c1265c2. We do not assume any lifting, and novelty of our method lies in our use of slopes of Frobenius and the slope spectral sequence. We also construct new birational invariants of surfaces. Applying our methods to threefolds, we characterize Calabi–Yau threefolds with b3= 0. We show that for any Calabi–Yau threefold b2>c3/2-1 and that threefolds which lie on the line b2= c3/ 2 - 1 are precisely those with b3= 0 and threefolds with b2= c3/ 2 are characterized as Hodge–Witt rigid (included are rigid Calabi–Yau threefolds which have torsion-free crystalline cohomology and whose Hodge–de Rham spectral sequence degenerates).

Original languageEnglish (US)
Pages (from-to)1111-1175
Number of pages65
JournalEuropean Journal of Mathematics
Issue number4
StatePublished - Dec 2020


  • Algebraic surfaces
  • Bogomolov–Miyaoka–Yau inequality
  • Calabi–Yau varieties
  • Chern number inequalities
  • Crystalline cohomology
  • Domino numbers
  • Frobenius split varieties
  • Hodge–Witt numbers
  • Hypersurfaces
  • Projective surfaces
  • Quintic threefolds
  • de Rham–Witt complex

ASJC Scopus subject areas

  • General Mathematics


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