If you are interested in doing a PhD under my supervision, you should apply to the Berlin Mathematical School (Phase II). This generally works best if I know enough about you to enthusiastically support your application, so for that reason it's a good idea to contact me ahead of time. (In some cases there may also be funding available that you would need to apply for separately from the BMS --- if so, I will tell you.)
Please note: While I make an effort to respond politely to all serious inquiries from prospective Ph.D. students, I do regularly also receive inquiries that make an "unserious" impression, which I usually leave unanswered. Your inquiry will typically be categorized as unserious if it fails to communicate to me that you have some nontrivial background knowledge in my research area (symplectic topology).
Prospective Master's students from outside of Humboldt University can also apply to the Master's Programme ("Phase I") of the Berlin Mathematical School.
Wer bei mir eine Bachelorarbeit schreiben möchte sollte in der Regel mindestens 3 von den folgenden 4 Vorlesungen gehört haben oder aktuell hören: Differentialgeometrie 1, Topologie 1, Topologie 2, Funktionalanalysis.