Yunqing Tang E-mail:  yunqingt at math dot princeton dot edu I am an instructor at Princeton University since July 2017. I recently graduated from Harvard University under supervision of Mark Kisin and I was a member at IAS during the academic year 2016-2017. Here is my CV.

Research articles

• Reductions of abelian surfaces over global function fields, with Davesh Maulik and Ananth Shankar, preprint.
  For a non-isotrivial ordinary abelian surface A over a global function field with good reduction everywhere, we prove that under mild conditions, there are infinitely many places modulo which A is isogenous to the product of two elliptic curves.


• Newton polygon stratification of the Torelli locus in PEL-type Shimura varieties, with Wanlin Li, Elena Mantovan, and Rachel Pries, submitted.
  We develop a clutching method to show that the intersection of the Torelli locus with some Newton strata in certain PEL-type Shimura varieties is non-empty with applications to Moonen's families and unlikely intersection of Torelli locus with certain Newton strata in A_g.


• Exceptional splitting of reductions of abelian surfaces, with Ananth Shankar, submitted.
  We prove that an abelian surface with real multiplication over a number field has infinitely many places of geometrically nonsimple reduction.


• Newton polygons arising for special families of cyclic covers of the projective line, with Wanlin Li, Elena Mantovan, and Rachel Pries, to appear in Research in Number Theory.
  We produce multiple new examples of Newton polygons and Ekedahl–Oort types of Jacobians of smooth curves in characteristic p from twenty special families of curves in Moonen's work.


• Newton polygons of cyclic covers of the projective line branched at three points, with Wanlin Li, Elena Mantovan, and Rachel Pries, to appear in Research Directions in Number Theory: Women in Numbers IV.
  We produce multiple new examples of Newton polygons that occur for Jacobians of smooth curves in characteristic p from such cyclic covers.


• Effective bounds for Brauer groups of Kummer surfaces over number fields, with Victoria Cantoral-Farfan, Sho Tanimoto, and Erik Visse, Journal of the London Mathematical Society Volume 97, Issue 3 (2018), pp. 353-376
  We study effective bounds for Brauer groups of Kummer surfaces associated to Jacobians of genus 2 curves defined over number fields.


• Cycles in the de Rham cohomology of abelian varieties over number fields, Compositio Mathematica 154 (2018), no.4, pp. 850--882.
  We prove the conjecture of Ogus that absolute Tate cycles are the same as Hodge cycles for some classes of abelian varieties.


• Algebraic solutions of differential equations over the projective line minus three points, International Journal of Number Theory Volume No.14, Issue No. 05 (2018), pp. 1427–1457.
  We prove a variant of the Grothendieck--Katz p-curvature conjecture under certain convergence condition for all finite places.