Workshop on Nonlinear Algebra

TU Berlin, March 26-27, 2020


This workshop celebrates the accomplishments of the Einstein project that started in April 2015 and ends in July 2020. The original proposal centered around 20 concrete problems that were organized into four themes: maximum likelihood geometry, euclidean distance optimization, convex algebraic geometry, and classical moduli spaces. More than half of the 20 problems have since been solved. The problems and their solutions will be featured in the one-hour lectures, while the shorter lectures present recent research results on other topics in Nonlinear Algebra.
The support of the Einstein Foundation and MPI for Mathematics in the Sciences in Leipzig is gratefully acknowledged.



The abstracts can be found here.

Thursday, March 26th
09:00-09:20 Registration Title
09:20 - 09:30 Welcome
09:30 - 10:30 Kaie Kubjas (Aalto University) Nonnegative rank: Rational factorizations, boundaries
and semi-algebraic characterizations
10:30 - 11:00 Coffee Break
11:00 - 11:30 Benjamin Schröter (Binghamton University) An update on the tropical Grassmannians and Dressians
11:30 - 12:30 Diego Cifuentes (MIT) The geometry of SDP relaxations
12:30 - 14:00 Lunch
14:00 - 14:30 Carlos Améndola (TU Munich) Invariant Theory and Iterative Proportional Scaling
for Maximum Likelihood Estimation
14:30 - 15:00 Fatemeh Mohammadi (University of Bristol) Algebra and Combinatorics of Conditional Independence
Models with Hidden Variables
15:00 - 15:30 Coffee Break
15:30 - 16:30 Jose Israel Rodriguez (University of Wisconsin - Madison) Critical points, Euler characteristics, and nearest
point problems
16:30 - 17:00 Sascha Timme (TU Berlin) Estimating linear covariance models with numerical
nonlinear algebra
19:00 Social Dinner*

Friday, March 27th
09:30 - 10:30 Marta Panizzut (TU Berlin) Moduli space of tropical cubic surfaces
10:30 - 11:00 Coffee Break
11:00 - 11:30 Kathlén Kohn (KTH Stockholm) Minimal Problems in Computer Vision
11:30 - 12:30 Emre Sertöz (MPI MiS Leipzig) Developing a calculus for periods of varieties
12:30 - 14:00 Lunch
14:00 - 14:30 Alheydis Geiger (Universität Tübingen) A tropical count of binodal cubic surfaces
14:30 - 15:00 Ben Smith (University of Manchester) Face posets of tropical polyhedra
15:00 - 15:30 Coffee Break
15:30 - 16:30 Dhruv Ranganathan (University of Cambridge)


If you plan to attend this workshop, please register by sending an e-mail to Antje Schulz (
To help us smooth out the organization, please use the subject line 'Registration NLA' for your e-mail.


All the talks will be held in room MA 042 in the Institute of Mathematics at TU Berlin. The coffee breaks will take place in room MA 141.
*The social dinner will be self paid.