A small number of departments within the RU together bought a network license for the concurrent use (by a small number of people) of Mathematica. If a department contributes to the payment of the license, one can get the installation and license information from C&CZ system administration. Incidental use by others is possible too, because C&CZ also bought 1 license.
The use of Mathematica is logged by the license server. If a department regularly uses Mathematica without having participated in the license, one can contact Ben Polman. The number of concurrent user licenses should be stated.
On the Linux PCs that are managed by C&CZ, Mathematica can be found in /vol/mathematica. On MS-Windows PC's Mathematica can be found on the S-disk (software).