Research

Chi cerca trova, chi ricerca ritrova. - Ennio De Giorgi

I work in the areas of Number Theory and Algebraic Geometry, because I study algebraic groups defined over number fields.

The aim of my research is understanding how the properties of algebraic groups and their points can be (algorithmically) detected from their reductions.

Publications and Preprints

  • On the order of the reductions of points on abelian varieties and tori, Ph.D. Thesis (defended in January 2009), pdf
  • Prescribing valuations of the order of a point in the reductions of abelian varieties and tori, J. Number Theory, vol. 129 (2009), no.2, 469-476.
  • Two variants of the support problem for products of abelian varieties and tori, J. Number Theory, vol. 129 (2009), no.8, 1883-1892.
  • with Peter Jossen, A counterexample to the local-global principle of linear dependence for Abelian varieties , C. R. Acad. Sci. Paris, Ser. I 348 (2010), no.1, 9–10. Presented by J-P. Serre.
  • On the problem of detecting linear dependence for products of abelian varieties and tori, Acta Arith., vol. 142 (2010), no.2, 119-128.
  • L'ordine dei punti nelle riduzioni di varietà abeliane e tori, Unione Matematica Italiana, La Matematica nella società e nella cultura, Serie I, vol. 3 (2010), no.1, 128-131.
  • On the reduction of points on abelian varieties and tori, Int. Math. Res. Notices, vol. 2011 (2011), no.7, 293-308.
  • The multilinear support problem for products of abelian varieties and tori, Int. J. Number Theory, vol. 8 (2012), no.1, 1-10.
  • with Chris Hall, On the prime divisors of the number of points on an elliptic curve, C. R. Acad. Sci. Paris, Ser. I 351 (2013) 1-3. Presented by J-P. Serre.
  • with Jeroen Demeyer, The constant of the support problem for abelian varieties, J. Number Theory, vol. 133 (2013), no.8, 2843-2856.
  • with Chris Hall, Characterizing abelian varieties by the reductions of the Mordell-Weil group, Pacific J. Math., vol. 265 (2013), no.2, 427-440.
  • The order of the reductions of an algebraic integer, J. Number Theory, vol. 148 (2015), 121-136.
  • The prime divisors of the number of points on abelian varieties, J. Théor. Nombres Bordeaux, vol. 27 no. 3 (2015), 805-814.
  • with Christophe Debry, Reductions of algebraic integers, J. Number Theory, vol. 167 (2016), no.1, 259-283.
  • Reductions of one-dimensional tori, Int. J. Number Theory, vol. 13 (2017), no. 1, 1473-1489.
  • Reductions of algebraic integers II, to appear in the Proceedings of WINE2 (2017).
  • Reductions of one-dimensional tori II, to appear in the Proceedings of WINE2 (2017).
  • with Davide Lombardo, The 1-eigenspace for matrices in GL2(ℤℓ), New York J. Math., vol. 23 (2017), 897-925.
  • with Davide Lombardo, Reductions of points on algebraic groups, preprint 2017.
  • Multiplicative order and Frobenius symbol for the reductions of number fields, preprint 2017.
  • with Peter Bruin, Reductions of points on algebraic groups II, preprint 2018.

Other projects and Notes

  • Elliptic curves over finite fields with many points (following Waterhouse's 1969 paper), pdf.
  • On the introductory notes on Artin's Conjecture (some details made explicit for students), pdf.
  • Foliazioni semiolomorfe e sottovarietà Levi piatte di una varietà complessa (Master thesis, new result about 1-dimensional holomorphic foliations), pdf.
  • Some variants of the intermediate value theorem for the rationals, pdf.
  • M. Akhim, KU Leuven Master thesis: Elliptic nets and their use in Cryptography (a new algorithm for elliptic nets is developed, the Sage code is included), pdf.
  • C. Debry, KU Leuven Master thesis: Beyond two criteria for supersingularity: coefficients of division polynomials, J. Théorie des Nombres de Bordeaux, vol. 26 (2014), no.3, 595-606, arXiv.
  • by J-P. Serre (Lettre du 3 nov. 2008), A set of prime numbers without a Dirichlet density, pdf.

Coauthors

Peter Bruin, Christophe Debry, Jeroen Demeyer, Chris Hall, Peter Jossen, Davide Lombardo,