Harry Richman

I am interested in problems in phylogenetics, tropical geometry (what's that??), combinatorics, and number theory.

I am currently a postdoc in the Matsen group, part of the Herbold Computational Biology Program at the Fred Hutch Cancer Center. I was previously a postdoc at the University of Washington where my mentor was Farbod Shokrieh. Before that I was a graduate student at the University of Michigan where my advisors were David Speyer and Jeff Lagarias. I was on the academic job market in fall 2019.

Before graduate school I studied math at MIT and the Math in Moscow program.


email: hrichman (аt) alum (dot) mit (dot) edu
github: harryrichman


Spring 2022: Math 208
Winter 2022: Math 208
Winter 2022: WXML Counting spanning trees
Autumn 2021: WXML Counting spanning trees
Summer 2021: MREG Rational Catalan combinatorics
Spring 2021: Math 308
Autumn 2020: Math 308 (linear algebra)
Winter 2019: Math 116, Origami on Lattices
Winter 2018: Math 116
Fall 2016: Math 215 (multivariable calculus)
Winter 2016: Math 116
Fall 2015: Math 216 (differential equations)
Winter 2015: Math 116 (calculus II)
Fall 2014: Math 115 (calculus I)


My work can be found on arXiv, Google Scholar, MathSciNet, ORCID, and zbMATH.


  1. "Minors of tree distance matrices," coauthored with Farbod Shokrieh and Chenxi Wu, in preparation.
    local: link
  2. "A Ricci flow on graphs from effective resistance," coauthored with A. Dawkins, V. Gupta, M. Kempton, W. Linz, J. Quail, and Z. Stier, in preparation.
  3. "The Möbius function of the poset of triangular numbers under divisibility," coauthored with Rohan Pandey, submitted.
  4. "The family of a-floor quotient partial orders," coauthored with Jeffrey Lagarias, submitted.
  5. "Counting two-forests and random cut size via potential theory," coauthored with Farbod Shokrieh and Chenxi Wu, submitted.
  6. "Tropical Weierstrass points and Weierstrass weights," coauthored with Omid Amini and Lucas Gierczak, submitted.


  1. "Lower rational approximations and Farey staircases," accepted for publication in Integers.
  2. "The distribution of Weierstrass points on a tropical curve," accepted for publication in Selecta Math.
    arXiv:1809.07920. DOI: 10.1007/s00029-024-00919-5.
  3. "The floor quotient partial order," coauthored with Jeffrey Lagarias. Advances in Applied Mathematics 153 (2024).
    arXiv:2212.11689. DOI: 10.1016/j.aam.2023.102615.
  4. "The tropical Manin-Mumford conjecture," International Mathematics Research Notices 2023.21 (2023), pp. 18714-18751.
    arXiv:2112.00168. DOI: 10.1093/imrn/rnad098.
  5. "Counting tripods on the torus," coauthored with Jayadev S. Athreya and David Aulicino. Arnold Mathematical Journal 9 (2023), pp. 359-379.
    arXiv:2111.01891. DOI: 10.1007/s40598-022-00216-z.
  6. "Derangements and the p-adic incomplete gamma function," coauthored with Andrew O'Desky. Transactions of the American Mathematical Society 376 (2023), pp. 1065-1087.
    arXiv:2012.04615. DOI: 10.1090/tran/8716.
  7. "Dilated floor functions having nonnegative commutator II. Negative dilations," coauthored with Jeffrey Lagarias. Acta Arithmetica 196.2 (2020), pp. 163-186.
    arXiv:1907.09641. DOI: 10.4064/aa190628-14-1.
  8. "Dilated floor functions having nonnegative commutator I. Positive and mixed sign dilations," coauthored with Jeffrey Lagarias. Acta Arithmetica 187.3 (2019), pp. 271-299.
    arXiv:1806.00579. DOI: 10.4064/aa180602-21-9.
  9. "Dilated floor functions that commute," coauthored with J. C. Lagarias and T. Murayama. American Math. Monthly 123.10 (2016), pp. 1033-1038.
    arXiv:1611.05513. DOI: 10.4169/amer.math.monthly.123.10.1033.

Ph.D. thesis

  1. "Weierstrass points and torsion points on tropical curves."
    official version: link (local link)

Notes and Presentations


Analysis quals
Rubik's cube
Quotes about math
Origami simulator built by Amanda Ghassaei
Multiline formulas guidelines provided by Acta Arithmetica
Math Subject Classification browse and search, resource from zbMATH
OEIS Online Encyclopedia of Integer Sequences
FindStat database and search engine for combinatorial statistics and maps
Eugenia Cheng on the lecture system
Why should I do math? Reasons by Tao Lin (43., 35., 31., 10., 28., 8., 11., 14., 41., 26., 21., 18.)