Jens Forsgård
Postdoc, Universiteit Utrecht
Mathematical Institute
Utrecht University
P.O. Box 80010
3508 TA Utrecht
The Netherlands
E-mail: j.b.forsgaard -at-

Photos taken by Elis Forsgård, Lionel Lang, and Hilary Page.

My CV is available here.

Last updated on 9 January 2019.


I am interested in geometry of zeros, tropical geomtry and (co)amoebas, toric geometry and polytopes, A-hypergeometric functions, and positivity.

I am currently a Postdoc at Universiteit Utrecht, where my mentor is Professor Frits Beukers. Before, I was a Post-doctorant (Postdoctoral Scholar) at Université de Genève, with Professor Grigory Mikhalkin, and a Visiting Assistant Professor at Texas A&M University, mentored by Professor Laura Felicia Matusevich. I obtained my Ph.D. at Stockholm University under the supervision of Professor Boris Shapiro. I was a student of Mikael Passare at the time of his death.


Recent preprints
  1. The algebraic boundary of the sonc cone, with T. de Wolff, arXiv:1905.04776.

  2. The Lattice of Amoebas, with T. de Wolff, arXiv:1711.02705.

  3. New subexponential fewnomial hypersurface bounds, with M. Nisse and J. Maurice Rojas, arXiv:1710.00481.

  4. On transformations of A-hypergeometric functions, with L. F. Matusevich and A. Sobieska, to appear in Funkcialaj Ekvacioj, arXiv:1703.03036.

  5. On the multivariate Fujiwara bound for exponential sums, submitted, arXiv:1612.03738.

  6. Discriminant amoebas and lopsidedness, to appear in Journal of Commutative Algebra.

Published Papers
In reverse chronological order.
  1. On dimer models and coamoebas, Ann. Inst. Henri Poincaré D 6 (2019), no. 2, 199–219, doi:10.4171/AIHPD/69, arXiv:1602.01826.

  2. Defective dual varieties for real spectra, J. Algebraic Combin. 49 (2019), no. 1, 49–67, doi:10.1007/s10801-018-0816-4, arXiv:1710.02434.

  3. Lopsided approximation of amoebas, with L. F. Matusevich, N. Mehlhop, and T. de Wolff, Math. Comp. 88 (2019), no. 315, 485–500, doi:10.1090/mcom/3323, arXiv:1608.08663. (An implementation can be found here.)

  4. On the parametric behavior of A-hypergeometric series, with C. Berkesch Zamaere and L. F. Matusevich, Trans. Amer. Math. Soc. 370 (2018), no. 6, 4089–4109, doi:10.1090/tran/7071, arXiv:1603.08954.

  5. Coamoebas of polynomials supported on circuits, in Analysis Meets Geometry, The Mikael Passare Memorial Volume (Andersson, Boman, Kiselman, Kurasov, and Sigurdsson, eds.), Trends in Mathematics, Birkhäuser, Basel, 2017, pp. 191–212, doi:10.1007/978-3-319-52471-9_13, arXiv:1601.05468.

  6. A tropical analog of Descartes' rule of signs, with D. Novikov and B. Shapiro, Int. Math. Res. Notices 2017 (2017), no. 12, 3726–3750, doi:10.1093/imrn/rnw118, arXiv:1510.03257.

  7. Hypergeometric functions for projective toric curves, with C. Berkesch Zamaere and L. F. Matusevich, Adv. Math. 300 (2016), 835–867, doi:10.1016/j.aim.2016.03.032, arXiv:1412.3957.

  8. Could Renè Descartes have known this?, with B. Shapiro and V. P. Kostov, Exp. Math. 24 (2015), no. 4, 438–448, doi:10.1080/10586458.2015.1030051, arXiv:1501.00856. (1501_Descartes.nb.) See also the corrigendum.

  9. On the order map for hypersurface coamoebas, with P. Johansson, Ark. Mat. 53 (2015), no. 1, 79–104, doi:10.1007/s11512-013-0195-y, arXiv:1205.2014.

  10. Coamoebas and line arrangements in dimension two, with P. Johansson, Math. Z. 278 (2014), no. 1–2, 25–38, doi:10.1007/s00209-014-1303-9.

  11. Euler–Mellin integrals and A-hypergeometric functions, with C. Berkesch and M. Passare, Michigan Math. J. 63 (2014), no. 1, 101–123, doi:10.1307/mmj/1395234361, arXiv:1103.6273.

Other publications
  1. A Mathematica notebook for computatins with discriminants is available here.

  2. A Mathematica notebook for computatins with dimer models is available here.

  3. Coamoebas of bivariate multi-affine polynomials.

  4. Rullgård's wild guess is false.

  5. A Mathematica notebook for drawing coamoebas is available here.

  6. Tropical aspects of real polynomials and hypergeometric functions, doctoral thesis, Stockholm University, 2015. Available here.

  7. On hypersurface coamoebas and integral representations of A-hypergeometric functions, licentiate thesis, Stockholm University, 2012. Available here.

Previous affiliations