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About Me

I'm currently employed as a Research Engineer at iText in Ghent. I was a researcher at KU Leuven from 2016 to 2020, where I completed my PhD in mathematics under the supervision of prof. Stefaan Vaes. My research centred around the representation theory of rigid C*-tensor categories, subfactor theory and quantum groups.

Want to get in touch? Then drop me a message at matthias@mvalvekens.be.

Tools & technology

I'm most comfortable in Python (3.x) and Java (1.7+). I've also worked with Haskell (ghc 8.x) and Javascript (ES6) in the past, and dabbled in C and Common Lisp. I learned the ropes fiddling around with calculators, which has left me with a fairly solid foundation in Zilog Z80 assembly — abstraction, what's that?

Jokes aside, I'm a big fan of the functional programming philosophy in general, and the way I approach problems in software development tends to reflect that. That said, I'm always happy to try new things and expand my toolbox.

Tinkering with software is my hobby: my trusty Raspberry Pi performs all sorts of useful and less-useful automation tasks, and I've got more silly project ideas than I'll ever have time to implement. This has made me a firm believer in the power of open source tooling and open standards to promote innovation.

Here's a non-exhaustive list of other, more specific tools I've used so far:

  • Django
  • git
  • LaTeX
  • PostgreSQL
  • nginx
  • Flask
  • celery
  • OpenSSL
  • GPG
  • postfix
  • dovecot
  • Mailman 3/Postorius/Hyperkitty
  • docker
  • CalDAV/CardDAV
  • uWSGI
  • Vaadin
  • certbot
  • GnuCash
  • Django
  • git
  • LaTeX
  • GPG
  • postfix
  • dovecot
  • docker
  • certbot
  • GnuCash
  • PostgreSQL
  • nginx
  • Flask
  • celery
  • OpenSSL
  • Mailman 3/Postorius/Hyperkitty
  • CalDAV/CardDAV
  • uWSGI
  • Vaadin

Side projects

  • pyHanko
    Sign PDFs using Python. Includes support for PKCS11 devices in general, and the Belgian eID in particular. PyHanko also deals with all baseline PAdES profiles. This project is currently in alpha.
  • certomancer
    Quickly construct, mock and deploy PKI test configurations using simple, declarative YAML config. Includes integrated CRL, OCSP and time stamping service provisioning. Certomancer provides a standalone WSGI application with minimal setup requirements, and also integrates with requests-mock. This tool is heavily used in pyHanko's test suite.
  • django-webauth
    Django reusable app that provides a collection of utilities on top of Django's standard django.contrib.auth package and django-otp. The feature set includes a minimal user model, support for token-based authentication, a simple and relatively boilerplate-free way to define JSON APIs with pluggable authentication workflows, and a flexible template-based multilingual mail broadcast mechanism.
  • django-double-entry
    Django reusable app to provide support for basic double-entry bookkeeping in the Django ORM. It also implements a highly customisable transaction processing API (implemented via django-webauth). The code is well-tested and has been running in production systems for about two years now.
  • django-partial-state
    Support for transparent handling of incomplete objects in the Django ORM.
  • Boggle
    A fairly basic Boggle clone with a Bulma-based user interface and a server running on top of Flask. Communication between client and server happens through a very simple JSON API. Goal: provide some responsible family entertainment during the coronavirus crisis. You can play around with it here.

Mathematical writings

Research articles

  1. D. Kyed, S. Raum, S. Vaes, and M. Valvekens, L2-Betti numbers of rigid C*-tensor categories and discrete quantum groups, Analysis & PDE 10 (2017), no. 7, 1757–1791. arXiv:1701.06447
  2. S. Vaes and M. Valvekens, Property (T) discrete quantum groups and subfactors with triangle presentations, Advances in Mathematics 345 (2019), 382–428. arXiv:1804.04006
  3. M. Valvekens, L2-Betti numbers of rigid C*-tensor categories associated with totally disconnected groups, International Mathematics Research Notices (to appear). arXiv:2001.10757

PhD thesis

M. Valvekens, L2-Betti numbers for subfactors and rigid C*-tensor categories, KU Leuven (2020).

The complete thesis is available here. Source code for the algorithms discussed in the appendix can be made available upon request.


Other

M. Valvekens, Some remarks on free products of rigid C*-2-categories, expository note (2020). arXiv:2008.12994

Miscellanea

I speak Dutch, English, Japanese and French, and I'm involved with several choirs in and around Leuven.