Are the TOEFL or IELTS mandatory? What is the required score?
So far neither of these tests is mandatory. However, we expect from every applicant to have a good (written and spoken) command of the English language. Providing test results helps us to judge and compare the language skills of the candidates.

Are there any tuition fees for the training programme?
First of all, students of the school will receive a stipend which fully covers living expenses in Dresden. There are no tuition fees with the exception of a nominal enrollment fee at the Technische Universität Dresden of about 170 Euro per term which already includes free public transport.

What are the regulations for the PhD defense?
Also that varies between different universities. At the faculty of mathematics and natural sciences at the Technische Universität Dresden, the actual defense, after the dissertation has been accepted by the committee, consists of a so-called 'Rigorosum' (non-public exam about two selected topics, ca. 45 minutes) and a public disputation. The latter comprises a talk by the PhD student (ca. 30 minutes), followed by a public scientific discussion. There is also an alternative procedure to the 'Rigorosum', which allows you to do the two exams beforehand. If you choose this option, it has to be approved by the faculty and there is an additional requirement to attend lectures in the amount of 20 SWS ('Semesterwochenstunden' - number of hours per week in a given term). Some of the lectures offerd within the IMPRS can count as such. PLEASE NOTE: These are just guidelines provided by the IMPRS to help you plan your PhD, which have no formal/legal validity!
Below, you can find some official links / forms of the faculty of mathematics and natural sciences at the Technische Universität Dresden on this topic.

• helpful guidelines (in English)
• Promotionsordnung
• Ordnung für das Promotionsstudium
• Form to apply for alternative rigorosum
• Form to confirm attendance of the 20 SWS of lectures

Further help can be found in the PhD student Wiki of the mpipks (only accessable from within mpipks).

Are there any teaching duties for PhD students?
That depends on the university by which the PhD degree is to be awarded. At the Technische Universität Dresden, there may indeed be some teaching obligations, like tutoring excercise groups or supervising undergraduate labs during one or two terms. Note that this also applies if you are not affiliated with the TUD but another partner institution in Dresden like MPI-PKS or MPI-CPfS - it is the degree awarding institution that matters in this respect!