In a nutshell…

Mutually recursive Thanos

I enjoy mathematics, computer science, music. Currently I work as a professor at the IMD institute of the Universidade Federal do Rio Grande do Norte, Brazil.

I obtained my PhD in theoretical computer science from ENS de Lyon (team Plume of the LIP lab) under the supervision of Olivier Laurent.

I obtained my MSc in mathematical logic from MPLA, and my BSc in pure mathematics from the University of Athens.

Further, boring information can be found in my CV.

Under non-re-reconstruction

I’m re-reconstructing my website at the moment. This page is particularly outdated but I keep more specific parts of my website up to date; so… click around.


Long-haired Thanos

My current research interests include constructive mathematics, foundations of mathematics, formalization of mathematics, {type, category, proof} theory.

I am currently investigating type theories as foundations of mathematics and their use in proof assistants and the formalization of mathematics. I am also highly interested in (and very passionate about) teaching of mathematics and computation in general, and mathematics education as a research field, including the use of proof assistants and type theoretic foundations in teaching mathematics.

I have worked mostly on theory of programming languages and denotational semantics; specifically on disjunctive logic programs and their game semantics. I have extended the games of simple logic programs to cover logic programs with disjunction, and I have defined an abstract semantic framework which I have used to develop a method to transform any non-disjunctive semantics into a corresponding disjunctive one.

PhD thesis

On the semantics of disjunctive logic programs, defended on July 2nd, 2014.
download: thesis | defense.



Some talks

On the semantics of disjunctive logic programs
slides: [ Part I | Part II ]

  • UFRN, Natal, Brazil (Feb 2015);
  • Demokritos, Athens, Greece (Jan 2015).

A game semantics for disjunctive logic programs

  • UFMG, Belo Horizonte, Brazil (Mar 2014);
  • LIX, École Polytechnique, Paris, France (Jan 2013);
  • University of Bath, UK (Sep 2012);
  • University of Oxford, UK (May 2012).


Thanos photo

OpenBSD ∩ λProlog

Just in case the intersection of the set of OpenBSD users with the set of λProlog users is not a singleton (which is a conjecture yet to be proved, for the time being), you might find my notes on installing Teyjus on OpenBSD useful. My teyjus OpenBSD port is available there.


Not so funny

On Saturday, May 11th, 2013, in Brazil, I was shot in the back!


email:; telegram: @tsouanas; GitHub: tsouanas



More information about the courses I am currently teaching or have taught in the past can be found on my teaching page.

I have been writing a book based on my lecture notes (in Portuguese).

You can also find videos of some of my lectures, seminars, etc., on my YouTube Channel (in Portuguese).


My old home-studio

I like composing and some very few times performing music as well. Some pieces I have recorded: Relic, Words, and Lunaby. Here's Relic:

And here are three of my favorite, much older compositions, I think:

You can find more information about my music on


I love programming! In case you care about that (though really, you shouldn't), I mostly use Haskell, TeX, and the Unix shell. You can find a few old and not-so-useful programs I've written below. For newer and not-so-not-so-useful programs, check my GitHub page. If you are looking for some other software in which I'm listed as the author, feel free to drop me an email.

lookbusy screenshot

Look busy doing nothing. Pretty much what it says... So, your eco-friendly (room)mate/mom/dad/whatever keeps powering off your computer, after glancing at the screen and making the wise decision that "it just sits there wasting energy, it's not doing anything". Look no further, this program is for you: lookbusy.


TAPL book cover

Project site. Implementation in Haskell of various λ-calculus based systems found in Benjamin Pierce's book, Types and Programming Languages.

If you are interested in this, you may also want to check tapl-haskell, a similar, independent project.

If you have no idea what this book is all about, you probably couldn't care less about this program.

Due to some changes in recent versions of GHC, TsouTAPL won't compile anymore. Until I tweak I won't tweak those things that need tweaking (exercise for the reader), so let's pretend it's some kind of vintage attitude.


>>> Last update: Fri Apr 26 02:28:19 -03 2024 is hosted on
That's recursion for you.