Portrait by Tine
Blankenstein, 2002 (click in order to enhance); picture 10 years later (Luminy, february 2012), and Gil Cavalcanti's view (november 2013).

This is the Mathematics Football Team 2005 (University Competition; 9th place).

And this is the beautiful building I work in.

This site is under permanent construction.

I work at the Mathematics Department of the University of Utrecht.

Secret Home Page of this Department.

My e-mail address is `J.vanOosten AT uu.nl`.

My office phone number is `+31 30 2533305`.

I used to work in the group of Ieke Moerdijk (you can admire him here), before he went to Nijmegen.

My research area is Mathematical Logic. Specifically, I am interested in the mathematics of various types of semantics for Intuitionistic Logic as well as in the metamathematics of intuitionistic formal systems. These interests involve Recursion Theory, Category Theory and the Proof Theory of Arithmetic.

A lot of my work has to do with Realizability. Here is a page with recent papers on Realizability and related subjects.

I have written a book on Realizability: *Realizability - An Introduction to its Categorical Side*, which has appeared March 2008 as Studies in Logic 152:

Here are Preface, Introduction and table of contents.

Here is a review of the book by Colin McLarty.

Here is the review of the book by Peter T. Johnstone, Bull. of Symbolic Logic 16 (3), September 2010, pp.407-409.

At this moment, the best place to buy the book appears to be amazon.ca. Go here for a site that compares prices of different Internet sellers.

I am *not* an intuitionist.

A few downloadable recent papers of mine.

Here are some slides of recent talks.

You find some lecture course material on my
teaching page.

Here is a link to the Mathematical Logic Colloquium.

And here is a link to my close friend and colleague Kuba Wschodni.

And here, you can see a few samples of my style of
refereeing.

*``It may be true that sadism is an important element in teaching, but it is better if it is at least
partly sublimated and not openly encouraged by being flaunted before an audience''* - Charles Rosen,
*Piano Notes*

Ein *Urteil* behauptet einen Sachverhalt; besteht dieser Sachverhalt, so ist das Urteil wahr, andernfalls unwahr.

Hermann Weyl, Das Kontinuum

Der Mensch kann denken, insofern er die Möglichkeit dazu hat.

Martin Heidegger, Was heisst Denken?

To every rule there is an exception. And the only exception to the rule, that to every rule there is an exception, is the rule that to every rule there is an exception.

Het aller-absoluutste niets

is van een niet-bestaande fiets

het niet met iets gevuld zijn van de

al evenmin bestaande banden.

Zou het dan gek zijn, vroeg een hond,

als daar geen fietspomp voor bestond?

K. Stip, *Op een hond*

Oh, there are *signs* of life in the university, I tell W. It *seems* that it's alive. But that life is the life of maggots, I tell W., devouring the substance of the university from the inside, living on its rotting.

The corpse of the university is a breeding ground, I tell W. The corpse is where Capital comes to lay its eggs. The university is that rotten place where Capital deposits its eggs...

Lars Iyer, *Exodus*

It is not necessary that you leave the house. Stay at your table and hearken. Don't even hearken, just wait. Don't even wait, be perfectly still and alone. There the world will offer herself to be unmasked, she must, she will writhe ecstatically before you.

Kafka, *Aphorismen-Zettelbuch 1920* (my translation)

Hier is een bijdrage aan de discussie rond Maarten van Buuren's *De afrekening*.

Hier is een bijdrage aan de discussie rond Dodenherdenking.

Hier is een Open brief aan Beatrix.

I wish you well.