Advisor and Mentor
The doctoral student will work under the supervision of a professor, the advisor, on a research project leading to a PhD Thesis as an independent piece of research.
The governing committee of the department of Mathematics has decided that each PhD student should also choose a Mentor. The mentor should be a trusted professor who will check on the progress of his or her mentees once a year. This professor should be your contact in case of issues you do not wish to discuss with your supervisor, and just generally someone to listen. It is adviseable to choose the mentor from outside the immediate study area. There is plenty of advice to the had on mathematics, but this is not what the mentor is supposed to be about.