Ishai Dan-Cohen


Mailing address:
Department of Mathematics
Ben-Gurion University of the Negev
P.O. Box 653
Be'er Sheva 8410501
Israel

Physical address: Building 58b (Deichman), Office 214

Tel.: (+972) 8 647 7862
E-mail: ishaida@bgu.ac.il

Political Disclaimer: I believe that actions such as prolonged occupation and genocide threaten to invalidate national sovereignty, and so to render the supposed need for national self-defense meaningless. For my part, I ask not to be considered responsible for the actions of any government that does not fully embrace the principles of democracy, including especially the principle of inaliable human rights.


Postdoctoral position available.

Research interests:

Algebraic geometry; especially integral points, motives, p-adic periods, and the unipotent fundamental group; Tannakian and homotopical methods.

Papers:

Joint with David Corwin: p-Adic periods and Selmer scheme images, arXiv preprint

Joint with Alexander Betts: A motivic Weil height machine for curves, arXiv preprint

On André periods of mixed Tate motives, arXiv preprint

Joint with Asaf Horev: Koszul duality for left modules over associative algebras, arXiv preprint

Joint with David Jarossay: M_{0,5}: Towards the Chabauty-Kim method in higher dimensions, Mathematica. arXiv preprint
Sage code for M_{0,5} over ZZ[1/6] in half-weight 4

Joint with David Corwin: The polylog quotient and the Goncharov quotient in computational Chabauty-Kim theory II , Transactions of the AMS. arXiv preprint

Joint with David Corwin: The polylog quotient and the Goncharov quotient in computational Chabauty-Kim theory I , International Journal of Number Theory. arXiv preprint

Joint with Tomer Schlank: Morphisms of rational motivic homotopy types, Applied Categorical Structures. arXiv:1811.06365

Joint with Tomer Schlank: Rational motivic path spaces and Kim's relative unipotent section conjecture, Rendiconti del Seminario Matematico della Universita di Padova. Unfortunately, the published version contains numerous errors of grammar and idiom. I recommend giving preference to the arXiv preprint. arXiv preprint , Corrigendum

Mixed Tate motives and the unit equation II, Algebra and Number Theory. arXiv preprint

Joint with Stefan Wewers: Mixed Tate motives and the unit equation, Int. Math. Res. Not. IMRN 2016, no. 17. (Associated Sage code: localanalytic.sage, lip.sage)

Joint with Jennifer Balakrishnan, Minhyong Kim, and Stefan Wewers: A non-abelian conjecture of Birch and Swinnerton-Dyer type for hyperbolic curves , Math. Ann. 372 (2018), no. 1-2, 369ג€“428. Erratum (Associated Sage code)

Joint with Stefan Wewers: Explicit Chabauty-Kim theory for the thrice punctured line in depth two, Proceedings of the London Math Society (2015) 110 (1): 133-171. arXiv preprint

Joint with Stefan Wewers: The Heisenberg coboundary equation: appendix to Explicit Chabauty-Kim theory

Moduli of unipotent representations II: wide representations and the width , Journal fur die Reine und angewandte Mathematik (Crelle's Journal), Volume 2015, Issue 699 (Feb 2015). Published version

Moduli of unipotent representations I: foundational topics, Annales de l'Institut Fourier, Vol. 62 no. 3 (2012), p. 1123-1187. Published version.

Moduli of unipotent representations, my thesis, largely subsumed by the two articles above.


Code:

Sage code for computing p-adic multiple polylogarithms, compiled jointly with Andre Chatzistamatiou: Read_Me_22 Main Subsidiary file Another subsidiary file

Seminars, Talks:

Web-page of the AGNT Seminar in BGU, Fall 2025 (with links to most other semesters)

Towards p-adic periods in Chabauty-Kim theory A video of a lecture given at Arithmetic, Geometry, Space and Time: a Workshop on the Occasion of Minhyong Kim’s 61st Birthday, 25 - 29 November 2024, ICMS Edinburgh. Lecture slides

A Motivic Weil height machine for curves, Diophantine days 2025, Westlake University, Hangzhou, China. Lecture slides

A Motivic Weil height machine for curves A video of a lecture given at the INI in May of 2022

Connectedness and concentration theorems in rational motivic homotopy theory A video of a lecture given at Banff in 2017

The polylog quotient and the Goncharov quotient in computational Chabauty-Kim theory A video of a lecture given at the Hausdorff Center for Mathematics in April of 2018

Towards Chabauty-Kim loci for the polylogarithmic quotient A video of a lecture given at the AMS Summer Institute in Algebraic Geometry in Salt Lake City in August of 2015

AGNT Seminar, Spring 2019

Slides for a talk in Konstanz:
Explicit Chabauty-Kim theory for the thrice punctured line

A seminar which I co-organized with Stefan Wewers:
"p-Adic structure of integral points" Program Schedule

A conference which I co-organized with Martin Olsson:
Equivariant algebraic geometry

Notes for expository talks:

The geometry of 3-Selmer classes, a talk about work of Cassels, O'Neil, and Fisher, apropos the work of Bhargava-Shankar on the BSD conjecture

The induction step in the wildly ramified higher class field theory of Kerz--Saito, February 2015 in Essen

Beilinson's conjectures on values of L-functions, Novermber 2014 in Essen

From cycle-complex constructions to Voevodsky motives, a talk about work of Bloch, Kriz, and Levine

The unipotent fundamental group is motivic, a talk about work of Wojtkowiak, Goncharov, Beilinson, and Deligne

Divisors and their intersections on wonderful compactifications, a talk about work of de Concini, Procesi

Bloch's formula and the Gersten resolution. I gave this talk at an introductory K-theory seminar, which followed the book by Srinivas.

Kim's Selmer variety, a talk about work of Minhyong Kim

Deligne's weight-monodromy theorem

A two-hour introduction to algebraic K-theory and Chern class maps

p-Adic heights and quadratic Chabauty, Fall 2023 learning seminar

The proétale topology on adic spaces, with a view towards the Hodge-Tate decomposition


This page was last modified on 31 January, 2026