Welcome to the Personal Website of

Philipp Reichenbach

"A mathematician is a machine for turning coffee into theorems."

Paul Erdös

About Me

I'm a PhD student in the group Algorithmic Algebra at the Institut für Mathematik of TU Berlin. My advisor is Prof. Dr. Peter Bürgisser and I'm part of his ERC Advanced Grant Project COCAN: Complexity and Condition in Algebra and Numerics.
Moreover, I'm a Phase II student at Berlin Mathematical School, a joint graduate school of the three Berlin universities.

Besides mathematics, I enjoy coffee, bouldering and listening to music.

Research Interests

Generally, I'm interested in Commutative Algebra, Algebraic Geometry, Representa­tion Theory, their interactions such as in Geometric Invariant Theory and their applications, e.g. Cryptography.
My PhD thesis- and ERC Project-research lie in the area of Computational Invariant Theory. This fascinating branch of mathematics combines many different fields like Geometric Invariant Theory, Symplectic Geometry, Discrete Geometry and Optimization.

Curriculum Vitae

Here you can find my CV as a pdf-file.

ORCID iD

ORCID iD iconhttps://orcid.org/0000-0002-5722-5505

News

  • Aug 2021: New preprint Symmetries in Directed Gaussian Graphical Models available; joint work with Visu Makam and Anna Seigal, see arXiv:2108.10058. We define restricted DAG (RDAG) models, given by a colouring on a directed acyclic graph. We study maximum likelihood estimation for these models and connections to Gaussian group models.
  • Jul 2021: The article Barriers for recent methods in geodesic optimization has been published in LIPIcs, Volume 200, 36th Computational Complexity Conference. This is joint work with Cole Franks, see DOI: 10.4230/LIPIcs.CCC.2021.13.
  • Jun 2021: The article Invariant Theory and Scaling Algorithms for Maximum Likelihood Estimation has been published in the SIAM Journal on Applied Algebra and Geometry. This is joint work with Carlos Améndola, Kathlén Kohn and Anna Seigal, see DOI: 10.1137/20M1328932.

Publications

Published (Peer-Reviewed)

Preprints

  • Symmetries in Directed Gaussian Graphical Models.
    With Visu Makam and Anna Seigal.
    arXiv:2108.10058.
  • Toric Invariant Theory for Maximum Likelihood Estimation in log-linear models.
    With Carlos Améndola, Kathlén Kohn and Anna Seigal. Submitted.
    arXiv:2012.07793.
  • Tensor Rank and Complexity.
    With Giorgio Ottaviani.
    arXiv:2004.01492.

Recent and Upcoming Activities

Aug 2021 SIAM Conference on Applied Algebraic Geometry 2021. Virtually at Texas A&M University, College Station, United States.
I give an invited talk about Transitive DAGs as Gaussian group models in the Minisymposium on Applied Invariant Theory: Statistics and Algorithms.
Aug 2021 Seminar on Nonlinear Algebra. MPI MiS, Leipzig, Germany.
On August 6th, I give a talk on Barriers for Scaling Algorithms in Invariant Theory.
Jul 2021 Computational Complexity Conference 2021. Virtually at Toronto, Ontario, Canada.
On July 21st, I give a talk on the accepted paper Barriers for recent methods in geodesic optimization.

Past Activities

May 2021 AMS Spring Western Sectional Meeting. Virtually at San Francisco State University, United States.
On May 2nd, I gave an invited talk about Invariant Theory for Maximum Likelihood Estimation in the Special Sesssion on Quivers, Tensors, and their Applications.
Mar 2021 9th BMS Student Conference. Virtually in Berlin, Germany.
Nov 2020 - Feb 2021 Polynomial Capacity: Theory, Applications, Generalizations. Online course by Jonathan Leake.
Mar 2020 - Mar 2021 Nonlinear Algebra Seminar Online NASO, organized by the Max-Planck-Institute for Mathematics in the Sciences, Leipzig, Germany.
I gave a talk titled Invariant Theory and Matrix Normal Models on April 21st, 2020.
Mar - Oct 2020 Reading group: From Euclidean to Geodesic Convex Optimization, Amsterdam, Netherlands.
Winter 2019/20 Thematic Einstein Semester: Varieties, Polyhedra, Computation. Berlin, Germany.
Feb 2020 Milestone Conference - TES: Varieties, Polyhedra, Computation. Berlin, Germany.
I gave a talk titled Invariant theory and scaling algorithms for maximum likelihood estimation.
Feb 2020 8th BMS Student Conference. Berlin, Germany.
Nov 2019 Buildings, Varieties, and Applications. Leipzig, Germany.
I gave a short talk titled Bounds on the weight margin.
Oct 2019 Opening Conference - TES: Varieties, Polyhedra, Computation. Berlin, Germany.
Oct 2019 Fall School - TES: Varieties, Polyhedra, Computation. Berlin, Germany.
Sep 2019 3rd Dr. Hans Riegel-Akademie. Brühl, Germany.
I gave a generally understandable talk on some applications of mathematics.
Aug 2019 Felipe's Fest: Complexity of Numerical Computation. Berlin, Germany.
Jul 2019 SIAM Conference on Applied Algebraic Geometry 2019. Bern, Switzerland.
May 2019 Euler Lecture by Claire Voisin. Potsdam, Germany.
Feb 2019 BMS Days and BMS Student Conference. Berlin, Germany.
Nov 2018 Talk on Vector bundles on elliptic curves and an associated Tannakian category. Forschungsseminar "Arithmetische Geometrie", HU Berlin, Germany.
Nov 2016 Talk on Stabilisator der Determinante und maximal lineare Teilräume. Dies Mathematicus 2016, TU Berlin, Germany.

Contact

Address
Technische Universität Berlin
Institut für Mathematik
Sekretariat MA 3-2
Straße des 17. Juni 136
10623 Berlin, Germany

Office
Room MA 319 (3rd floor)

eMail
reichenbach@tu-berlin.de