$$ \DeclareMathAlphabet{\matheuler}{U}{eus}{m}{n} \newcommand\F{\mathbb F} \newcommand\P{\mathbb P} \newcommand\A{\mathbb A} \newcommand\T{\mathbb T} \newcommand\msO{\mathscr O} \newcommand\msL{\mathscr L} \newcommand\ms{\mathscr} \newcommand\GL{\opname{GL}} \newcommand\eps{\varepsilon} \newcommand\opname{\operatorname} \newcommand\Proj{\opname{Proj}} \newcommand\Pic{\opname{Pic}} \newcommand\hom{\opname H} \newcommand\Char{\opname{char}} \newcommand\Hom{\opname{Hom}} \newcommand\Sel{\opname{Sel}} \newcommand\inv[2][1]{#2^{-#1}} \newcommand\pinv[2][1]{\inv[#1]{\p{#2}}} \newcommand\p[1]{\left(#1\right)} $$

Niven T. Achenjang


I am a math grad student at MIT, broadly interested in arithmetic geometry and especially in points on varieties. My advisor is Bjorn Poonen.

You can find my cv here, once I make an up to date one.

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Apr 2, 2024 I will be travelling to Seattle to talk in UW’s Number Theory Seminar. Exactly what I will talk about is still TBD.
Jan 2024 I gave a talk at JMM this year on my 2-Selmer paper. I will also be talking about it again soon at
Nov 29, 2023 Various coauthors and I posted a new paper on arxiv, in which we compute the Brauer group of the moduli stack \(\mathscr Y_0(2)\) parameterizing elliptic curves equipped with a cyclic subgroup of order \(2\).
Oct 12, 2023 I posted a new paper on arxiv. It is about bounding the average size of \(2\)-Selmer groups of elliptic curves \(E\) over characteristic \(2\) function fields. It also produces some new bounds on \(\dim_{\F_2}\Sel_2(E/K)\) when \(\Char K=2\) (and \(K\) is a global function field).
Aug 2023 I’m gonna try running a seminar on modularity and Fermat.


  1. ArXiv
    The Brauer Group of \(\mathscr Y_0(2)\)
    Achenjang, Niven, Bhamidipati, Deewang, Jha, Aashraya, Ji, Caleb, and Lopez, Rose
  2. ArXiv
    The Average Size of 2-Selmer Groups of Elliptic Curves in Characteristic 2
    Achenjang, Niven
  3. IMRN
    Integral Points on Varieties With Infinite Étale Fundamental Group
    Achenjang, Niven T, and Morrow, Jackson S
    International Mathematics Research Notices,  2023
  4. IJNT
    On gaps in the closures of images of divisor functions
    Achenjang, Niven, and Berger, Aaron
    International Journal of Number Theory,  2019