About me

I am an Associate Professor in the Department of Mathematics at Temple University.

Research interests

My research is largely focused on where the study of discrete subgroups of Lie groups intersects with algebraic geometry, low-dimensional topology, hyperbolic geometry, dynamics, and number theory. In some sense, the problems I study follow up on the work of Klein, Picard, and Poincaré, but from a more modern point of view deeply influenced by the Gromov-Thurston perspective on geometry and topology and the work of Margulis on dynamics and rigidity.

My work was awarded a 2023 Dean’s Distinguished Excellence in Research Award, and is currently support by NSF grant DMS-2203555.

Professional history

I graduated from the Maine School of Science and Mathematics in 1999 and the University of Chicago in 2003 with a BA in mathematics. My PhD is from the Department of Mathematics at the University of Texas at Austin in 2010, where my advisor was Alan W. Reid. From 2010 – 2013, I was an RTG Postdoctoral Assistant Professor in the Department of Mathematics at the University of Michigan.

I joined Temple in 2013 as an Assistant Professor, and was promoted to Associate Professor in 2019.

Publications

  1. Profinite rigidity amongst Kähler groups: Curves and subdirect products
    w/ Sam Hughes, Claudio Llosa Isenrich, Pierre Py, Ryan Spitler, and Stefano Vidussi
    In preparation
  2. High dimensional hyperbolic Coxeter groups that virtually fiber
    w/ Jean-François Lafont, Barry Minemyer, Gangotryi Sorcar, and Joseph Wells
    In preparation
  3. One-cusped complex hyperbolic 2-manifolds
    w/ Martin Deraux
    Submitted
    arxiv
  4. Residual finiteness and discrete subgroups of Lie groups
    Submitted
    arxiv
  5. Products of curves as ball quotients
    Submitted
    arxiv
  6. Rich representations and superrigidity
    w/ Gregorio Baldi, Nicholas Miller, and Emmanuel Ullmo
    To appear in Ergodic Theory Dynam. Systems
    arxiv
  7. Algebraic fundamental groups of fake projective planes
    To appear in J. Eur. Math. Soc. (JEMS)
    arxiv | magma file
  8. Geometry of the Wiman-Edge monodromy
    J. Topol. Anal. 15 (2023), no. 3, 815-843
    arxiv | magma and mathematica files
  9. Arithmeticity, superrigidity, and totally geodesic submanifolds of complex hyperbolic manifolds
    w/ Uri Bader, David Fisher, and Nicholas Miller
    Invent. Math. 233 (2023), no. 1, 169-222
    arxiv
  10. Congruence RFRS towers
    w/ Ian Agol and an appendix by Mehmet Haluk Şengün
    Ann. Inst. Fourier (Grenoble) 73 (2023), no. 1, 307–333
    arxiv
  11. Rigid surfaces arbitrarily close to the Bogomolov-Miyakoa-Yau line
    w/ Giancarlo Urzúa
    Amer. J. Math. 144 (2022), no. 6, 1783-1804
    arxiv | magma and mathematica files
  12. Residual finiteness for central extensions of lattices in PU(n,1) and negatively curved projective varieties
    w/ Domingo Toledo
    Pure Appl. Math. Q. 18 (2022), no. 4, 1771-1797 (Special issue celebrating the work of Herb Clemens)
    arxiv
  13. Residually finite lattices in \widetilde{PU}(2,1) and fundamental groups of smooth projective surfaces
    w/ Domingo Toledo
    Michigan Math. J. 72 (2022), 559-597 (Special Volume in Honor of Gopal Prasad)
    arxiv | mathematica files
  14. Azumaya algebras and canonical components
    w/ Ted Chinburg and Alan W. Reid
    Int. Math. Res. Not. IMRN 2022, no. 7, 4969-5036
    arxiv
  15. Finiteness of maximal geodesic submanifolds in hyperbolic hybrids
    w/ David Fisher, Jean-François Lafont, and Nicholas Miller
    J. Eur. Math. Soc. (JEMS) 23 (2021), no. 11, 3591-3623
    arxiv
  16. Arithmeticity, superrigidity, and totally geodesic submanifolds
    w/ Uri Bader, David Fisher, and Nicholas Miller
    Ann. of Math. (2) 193 (2021), no. 3, 837-861
    arxiv
  17. Cusp and b1 growth for ball quotients and maps onto Z with finitely generated kernel
    Indiana Univ. Math. J. 70 (2021), no. 1, 213-233
    arxiv
  18. Negative curves of small genus on surfaces
    w/ Ted Chinburg
    Math. Z. 295 (2020), no. 1-2, 309-330
    arxiv
  19. Lattices in PU(n,1) that are not profinitely rigid
    Proc. Amer. Math. Soc. 147 (2019), 5055-5062
    arxiv
  20. Punctured spheres in complex hyperbolic surfaces and bielliptic ball quotient compactifications
    w/ Luca F. Di Cerbo
    Trans. Amer. Math. Soc. 372 (2019), 4627-4646
    arxiv | magma file
  21. Commensurability classes of fake quadrics
    w/ Ben Linowitz and John Voight
    Selecta Math. (N.S.) 25 (2019), no. 3, 25:48
    arxiv
  22. New nonlinear hyperbolic groups
    w/ Richard D. Canary and Konstantinos Tsouvalas
    Bull. Lond. Math. Soc. 51 (2019), no. 3, 547-553
    arxiv
  23. On general type surfaces with q=1 and c2=3pg
    Manuscripta Math. 159 (2019), no. 1-2, 171-182
    arxiv
  24. Explicit bounds from the Alon-Boppana theorem
    w/ Joseph Richey and Noah Shutty
    Exp. Math. 27 (2018), no. 4, 444-453
    arxiv | python file
  25. Character varieties and actions on products of trees
    w/ David Fisher, Michael Larsen, and Ralf Spatzier
    Israel J. Math. 225 (2018), no. 2, 889-907
    arxiv
  26. Classification and arithmeticity of toroidal compactifications with c1^2 = 3 c2 = 3
    w/ Luca F. Di Cerbo
    Geom. Topol. 22 (2018), no. 4, 2465-2510
    arxiv
  27. Geodesic curves on Shimura surfaces
    w/ Ted Chinburg
    Topology Proc. 52 (2018), 113-121
    arxiv
  28. Constructing geometrically equivalent hyperbolic orbifolds
    w/ D. B. McReynolds and Jeffrey Meyer
    Algebr. Geom. Topol. 17 (2017), no. 2, 831-846
    arxiv
  29. Amalgam Anosov representations
    w/ Richard D. Canary and Michelle Lee
    Appendix: Convex Anosov Schottky groups
    w/ Richard D. Canary, Michelle Lee, and Andrés Sambarino
    Geom. Topol. 21 (2017), no. 1, 215-251
    arxiv
  30. Bielliptic ball quotient compactifications and lattices in PU(2,1) with finitely generated commutator subgroup
    w/ Luca F. Di Cerbo
    Ann. Inst. Fourier (Grenoble) 67 (2017), no. 1, 315-328
    arxiv
  31. Parametrizing Shimura subvarieties of A1 Shimura varieties and related geometric problems
    w/ Ben Linowitz
    Arch. Math. (Basel) 107 (2016), no. 3, 213-226
    arxiv
  32. Multiple realizations of varieties as ball quotient compactifications
    w/ Luca F. Di Cerbo
    Michigan Math. J. 65 (2016), no. 2, 441-447
    arxiv
  33. Presentations for quaternionic S-unit groups
    w/ T. Chinburg, H. Friedlander, S. Howe, M. Kosters, B. Singh, Y. Zhang, and P. Ziegler
    Exp. Math. 24 (2015), no. 2, 175-182
    arxiv
  34. Small generators for S-unit groups of division algebras
    w/ Ted Chinburg
    New York J. Math 20 (2014), 1175-1202
    arxiv
  35. Hurwitz ball quotients
    Math. Z. 277 (2014), no. 1-2, 75-91
    arxiv | magma file
  36. Covolumes of nonuniform lattices in PU(n,1)
    w/ Vincent Emery
    Amer. J. Math. 136 (2014), no. 1, 143-164
    arxiv
  37. Collisions at infinity in hyperbolic manifolds
    w/ D. B. McReynolds and Alan W. Reid
    Math. Proc. Cambridge Philos. Soc. 155 (2013), no. 3, 459-463
    arxiv
  38. On the number of ends of rank one locally symmetric spaces
    Geom. Topol. 17 (2013), no. 2, 905-924
    arxiv
  39. A Cantor set with hyperbolic complement
    w/ Juan Souto
    Conform. Geom. Dyn. 17 (2013), 58-67
    arxiv
  40. Arithmeticity of complex hyperbolic triangle groups
    Pacific J. Math. 257 (2012), no. 1, 243-256
    arxiv
  41. Cusps of Picard modular surfaces
    Geom. Dedicata 157 (2012), 239-257
    arxiv
  42. Volumes of Picard modular surfaces
    Proc. Amer. Math. Soc. 139 (2011), no. 9, 3045-3056
    arxiv | magma file
  43. Property (FA) and lattices in SU(2,1)
    Internat. J. Algebra Comput. 17 (2007), no. 7, 1335-1347
    arxiv | addendum

Conference organization

Temple University Graduate Student Conference in Algebra, Geometry, and Topology
Temple University
May 31 – June 2, 2024 (2025 dates TBA)

Hyperbolic Manifolds, their Submanifolds and Fundamental Groups
Instituto Nacional de Matemática Pura e Aplicada
January 6 – 10, 2025 with follow-up workshop January 13 – 17

Discrete Subgroups of Lie Groups: Dynamics, Actions, and Rigidity
July 7 – 18, 2025
Institut des Hautes Études Scientifiques

Hyperbolic 4-manifolds
Centre de Recherches Mathématiques
September 9 – 13, 2025

Contact and links

Email – (first initial)(lastname)@temple.edu

Office – Wachman 1024

Github repository