Jan Hagedoorn, a PhD student from GeoForschungsZentrum Potsdam, visited us for 3 months. His stay was oriented into the three issues. First, he continued in his PhD work on glacial isostatic adjustment (GIA). Particularly, he set up the benchmark study on the numerical implementation of sea-level equation in glacial isostatic adjustment and has invited us, as well as the other scientists, to contribute to this benchmark study. Second, he focused on the prediction of GIA-induced deformation and changes in the Earth's rotation on GPS and tide-gauge measurements. For this purpose, he installed his numerical software for modeling GIA coupled with sea-level equation and rotational deformation at one of our most powerful computers. This software can be used in MAGMA Centre for scientific purpose in future. Finally, Jan took part in the course "Selected chapters from partial differential equations", taught for undergraduate students of Geophysics at our Faculty by C. Matyska. He appreciated the high theoretical level of the lecture, which helped him to understand details of the GIA formulation developed at our Department.