Homepage of Benjamin Matthias Ruppik

I am a Machine Learning Researcher and Mathematician working at the intersection of Topological Deep Learning and Representation Learning, with a particular focus on applying Topological Data Analysis (TDA) to Natural Language Processing and Large Language Models.

My name is Ben Ruppik (he/him), and as a Postdoctoral researcher in the Dialog Systems and Machine Learning Lab led by Prof. Milica Gašić at Heinrich Heine University Düsseldorf, I am involved in the technical work of research projects covering natural language understanding, dialogue state tracking, RL policy learning, knowledge & ontology extraction, and natural language generation. My main expertise is in Topological Deep Learning and I use Topological Data Analysis (TDA) to study the latent spaces of large language models, with applications to task-oriented dialogue systems. I completed a Ph.D. in low-dimensional topology and knot theory at the Max Planck Institute for Mathematics and the University of Bonn, resulting in multiple peer-reviewed publications in mathematics research journals.

This website provides an overview of my ongoing research, publications, and selected projects. Feel free to get in touch via e-mail or LinkedIn in English or German.

GitHub; HuggingFace; LinkedIn; Bluesky; Xing; X; MathStackExchange.

Publications

Selected Papers and Preprints

For a complete list, follow the links to arXiv; ORCID iD icon ORCID; Google Scholar; ResearchGate; ACL Anthology.

Thesis

Iterated Whitehead double of the dual knot in the Poincare homology sphere

Casson-Whitney unknotting, Deep slice knots and Group trisections of knotted surface type

Advisors: Arunima Ray and Peter Teichner.

PhD thesis published at University of Bonn.

Main new results:
  • An explicit construction of regular homotopies between rim surgeries (which subsumes some of the previous applications to twist-spun knots).
  • A generalization of the fusion number upper bound for the Casson-Whitney number to higher genus ribbon surfaces in the 4-sphere.
  • The stabilization number of Suciu's ribbon 2-knots \(R_{k}\) is equal to 1.
  • The Casson-Whitney distance of the standard unknotted \(\mathbb{RP}^{2}\) and Suciu's associated \(\mathbb{RP}^{2}\)-knots \(R_{k} \# \mathbb{RP}^{2}\) is equal to 1.
  • Partial results of the algebraic Casson-Whitney number of Suciu's knots.
  • The (+1)-trace on the right handed trefoil knot contains infinitely many non-local knots in its boundary which exhibit the difference between shallow topological sliceness and smooth deep sliceness. This is an interplay between Freedman's construction of a topological slice for 3-fold iterated positively clasped Whitehead doubles on the one hand, and the Heegaard-Floer \(\tau\)-invariant giving a smooth obstruction for sliceness in \(\partial X \times [0,1]\).
  • Group trisections of knotted surface type of the trefoil group, which comes from a bridge trisection of Suciu's ribbon 2-knots.

Resources

Activities

Summer Term 2023

Teaching
Talks
Conferences

Winter Term 2022/2023

Teaching
Talks
Conferences

Summer Term 2022

Teaching
Conferences

Winter Term 2021/2022

Talks

Summer Term 2021

Talks
Conferences

Winter Term 2020/2021

Talks
Conferences

Summer Term 2020

Talks
Conferences/Workshops

Winter Term 2019/2020

Talks
Conferences
  • Winter Braids X, Pisa, February 17 - 21, 2020
  • Low-dimensional topology workshop, Regensburg, October 21 - 23, 2019.

Summer Term 2019

Talks
Conferences

Winter Term 2018/2019

Summer Term 2018

  • Material for the rep 'Introduction to Geometry and Topology' in the summer term 2018.

Winter Term 2017/2018

Summer Term 2017

  • Material for the rep 'Introduction to Geometry and Topology' in the summer term 2017.
  • Handout (.pdf) for a talk on the First Lie Theorem.

Summer Term 2016