My main research interests are computability theory, algorithmic randomness, reverse mathematics, higher recursion theory, computable model theory, and set theory.
From 2011 until 2015 I am a Rutherford Discovery fellow. From 2012 to 2015 I am a Turing Research fellow.
I am a co-organiser of the Semester in Computability, Complexity and Randomness in Buenos Aires in the first half of 2013.
I am chair of the programme committee for the 8th International Conference on Computability, Complexity and Randomness. Submissions are welcome.
The proof that there are incomparable Turing degrees is really intended as a joke; there have been some misunderstandings.