My PhD is about computer programming language semantics. This involves mathematically defining what a program does, thereby being able to prove things about its behaviour. More specifically, I work on denotational semantics for concurrency. I believe that in the not-too-distant future, every safety-critical program will not just be tested to work, but proven to be correct. Disasters caused by program errors such as the explosion of the Arianne 5 rocket in 1996 will be a matter of history. Hopefully my research will help to get a small step closer to this ultimate goal.