Felix Cherubini's Research Page

Hi, I am Felix Cherubini (birth name: Felix Wellen) and this is my research website.

Design of this page

I learned from a web-design expert in Germany, that the design of this page is utterly bad. Sorry if the design bothers you – I believe her, that it is quite bad, but I won't do anything about it any time soon. There are also no funny pictures of cats on this page, so if you were looking for that, you have to find that somewhere else on the internet.

Employment history

What my Research is About

I am interested in application of Homotopy Type Theory (HoTT) to Differential and Algebraic Geometry and, more generally, I want to know how well HoTT can help to make current research in pure mathematics more understandable. The approach I am using is based on Urs Schreiber's differential cohesion.

In early 2018, I wrote an essay describing my thesis for the German competition "Klartext!". It didn't win and it is in German, you can view it here.

You can also go to the nLab.

More recently, my approach to the story includes the possibility to make calculations, which is possible in the Kock-Lawvere like axioms of synthetic algebraic geometry. I use some axioms which I know about from Ingo Blechschmidt's thesis and David Jaz Myers. You can watch the latest code here.



I gave a lecture on HoTT at the University of Augsburg in the summer 2021. There is a german script.

Articles and Abstracts


Here is an overview of video recordings of talks about my topics:

This one might be the best place to start, if you want to understand the general direction of what I am interested in.

This one focuses on the cartan geometry from my thesis.

Those were tutorials 2 and 6, here is the complete list:

Tutorial 1 Dan Licata: A Fibrational Framework for Modal Simple Type Theories

Tutorial 2 Felix Wellen: The Shape Modality in Real cohesive HoTT and Covering Spaces

Tutorial 3 Dan Licata: Discrete and Codiscrete Modalities in Cohesive HoTT

Tutorial 4 Felix Wellen: Discrete and Codiscrete Modalities in Cohesive HoTT, II

Tutorial 5 Dan Licata: A Fibrational Framework for Modal Dependent Type Theories

Tutorial 6 Felix Wellen: Differential Cohesive HoTT


You can use the address felix.cherubini[at]posteo.de to contact me. There is also a pgp-key for this address with fingerprint 63E6 E9E2 D88A 267B 7A44 5A34 62D3 070A CDC1 004E