Jan Denef (born 4 September 1951) is a Belgian mathematician.
[1] Denef obtained his PhD from KU Leuven in 1975 with a thesis on Hilbert's tenth problem; his advisors were Louis Philippe Bouckaert and Willem Kuijk.
He is well known for his early work on Hilbert's tenth problem and for developing the theory of motivic integration in a series of papers with François Loeser.
Recently he proved a conjecture of Jean-Louis Colliot-Thélène which generalizes the Ax–Kochen theorem.
In 2002 Denef was an Invited Speaker at the International Congresses of Mathematicians in Beijing.