Andrew Obus

Andrew reading children's counting book

Baruch College
Department of Mathematics
1 Bernard Baruch Way
New York, NY 10010


Office Phone:  646-312-4008
Office: Baruch Vertical Campus 6-223, CUNY Graduate Center 4303

About Me: I am an associate professor in the Department of Mathematics at Baruch College, as well as doctoral faculty at the CUNY Graduate Center.  As you can see, I am also an artistic visionary in the field of web design.  My work is partially supported by NSF CAREER Grant DMS-2047638.

Here is my CV.

Research Publications

  1. Ramification of primes in fields of moduli of three-point covers, Ph. D. Thesis (2009), supervised by David Harbater at the University of Pennsylvania (vii+135 pp.)
  2. (with Rachel Pries) Wild tame-by-cyclic extensions, J. Pure Appl. Algebra(5) 214 (2010), 565–573
  3. Vanishing cycles and wild monodromy, Int. Math. Res. Notices (2012), 299–338
  4. Fields of moduli of three-point G-covers with cyclic p-Sylow, I, Algebra Number Theory, 6, (2012) no. 5, 833–883
  5. The (local) lifting problem for curvesProceedings for Conferences in Kyoto “Galois-Teichmüller theory and Arithmetic Geometry”(2012), 359–412
  6. Fields of moduli of three-point G-covers with cyclic p-Sylow, IIJ. Théor. Nombres Bordeaux 25, (2013) no. 3, 579–633
  7. Toward Abhyankar’s inertia conjecture for PSL_2(\ell)Proceedings of the Luminy Meeting “Groupes de Galois géométriques et différentiels” (2013), 195–206
  8. On Colmez’s product formula for periods of CM-abelian varietiesMath. Ann. 356, (2013) no. 2, 401–418
  9. Conductors of wild extensions of local fields, especially in mixed characteristic (0, 2), Proc. Amer. Math. Soc. 142 (2014) no. 5, 1485–1495
  10. (with Stefan Wewers) Cyclic extensions and the local lifting problemAnn. of Math. 180, (2014) no. 1, 233–284
  11. (with Stefan Wewers) Wild Ramification KinksRes. Math. Sci., 3:21 (2016), 27 pp.
  12. The local lifting problem for A_4Algebra Number Theory, 10, (2016) no. 8, 1683–1693
  13. Good reduction of three-point Galois coversAlgebraic Geometry, 4, (2017) no. 2, 247–262
  14. (with Colin Ingalls, Ekin Ozman, and Bianca Viray) Unramified Brauer Classes on cyclic covers of the projective plane (with an appendix by Hugh Thomas)Proceedings of the AIM Workshop, “Brauer groups and obstruction problems: Moduli and arithmetic” (2017), 115–153
  15. A generalization of the Oort conjectureComm. Math. Helv., 92, (2017) no. 3, 551–620
  16. (with David Harbater, Rachel Pries, and Kate Stevenson) Abhyankar’s conjectures in Galois theory: Current status and future questionsBull. Amer. Math. Soc., 55,  (2018) no. 2, 239–287.
  17. (with Hilaf Hasson) The abc conjecture implies the weak diversity conjectureAlbanian J. Math., 12, (2018) no. 1, 8–14
  18. (with John Doyle, Holly Krieger, Rachel Pries, Simon Rubinstein-Salzedo, and Lloyd West) Reduction of dynatomic curvesErgodic Theory Dynam. Systems, 38, (2019) no. 10, 2717–2768
  19. Lifting of curves with automorphisms, Open Problems in Arithmetic Algebraic Geometry, Adv. Lect. Math. (ALM) 46, F. Oort, ed. (2019), 9–59
  20. (with Stefan Wewers) Explicit resolution of weak wild quotient singularities of arithmetic surfaces, J. Algebraic Geom., 29, (2020) no. 4, 691–728
  21. (with Tony Shaska) Superelliptic curves with many automorphisms and CM JacobiansMath. Comp.90 (2021), 2951–2975
  22. (with Huy Dang, Soumyadip Das, Kostas Karagiannis, and Vaidehee Thatte) Local Oort groups and the isolated differential data criterion (16 pp.), J. Théor. Nombres Bordeaux, 34, (2022) no. 1, 251–269
  23. (with Padmavathi Srinivasan) Explicit minimal embedded resolutions of divisors on models of the projective lineRes. Number Theory,8, (2022), no. 2, Paper No. 27, 27 pp.
  24. (with Padmavathi Srinivasan) Conductor-discriminant inequality for hyperelliptic curves in odd residue characteristicInt. Math. Res. Notices, to appear, 13 pp.
  25. (with Daniele Turchetti) Stabilization indices of potentially Mumford curves, preprint, 33 pp.

Other Writings:

  1. Preparing for the Tenure-Track Job MarketNotices Amer. Math. Soc.67, (2020) no. 6, 807–809

Current Teaching (Spring 2024)

MTH 4010 (Mathematical Analysis I)
MTH 3035 (Vector Calculus)


I sit on the board of the I-HELP Liberia Project and have been involved in writing the Liberian Math Olympics contests. I traveled to Liberia in the Summers of 2011, 2013, and 2017 with groups representing the organization to help run two-week STEM teacher training workshops. Since August 2021, I have run a weekly training program for Liberian math teachers on Zoom.

The webpage for the Fall 2023 Liberian Mathematics Teacher Training Program is here.