Benjamin Rott obtained his PhD in Mathematics Education at the University of Hannover. Thereafter, he worked as a postdoctoral researcher at the University of Education Freiburg and at a Professor at the University of Duisburg-Essen. Since 2017, he is a Professor in the Institute of Mathematics Education at the University of Cologne. His research interests include mathematical problem solving, mathematical giftedness, and (epistemological) beliefs. Günter Törner obtained his PhD in Mathematics at the University of Gießen and habilitated within mathematics at the Technical University of Darmstadt. Since 1978, he has been working as a full professor for Mathematics at the University Duisburg-Essen. His research interests are pure mathematics, applied discrete mathematics and cooperation with companies. For seven years, he was the chair of the Committee of Education of the European Mathematical Society. He was a founding member of the DZLM. He isinvolved in initial teacher training and professional development for in- and pre-service teachers. He has published more than fifty mathematical papers, more than eighty papers within educational journals and international proceedings of conferences. He has supervised more than 23 PhD graduate students in the last years.Joyce Peters-Dasdemir is working on her PHD in the group of Prof. Dr. Barzel at the faculty for Mathematics at the University of Duisburg-Essen and she is occupied as a scientific researcher of the German Center for Mathematics Teacher Education (DZLM). She is involved in multiplier programs and professional development programs for in- and pre-service teachers and is active in the field of development coordination. Her research interests are development and implementation of PD Centers, conceptual knowledge, beliefs of teachers about digital technology, the use of digital technology in mathematics and science teaching and the influence of professional development programs on teaching.Anne Möller is a seconded teacher for Mathematics Education in the scientific group of Prof. Dr. Bärbel Barzel at the University of Duisburg-Essen and working on her PhD on teaching mathematics via problem solving supervised by Prof. Dr. Benjamin Rott, University of Cologne. Her research foci include the development and evaluation of using discovery learning and problem solving in class, and the analysis of teachers’ explanation of the use of discovery learning and problem solving in math lessons.Safrudiannur is a doctoral student in mathematics education at the University of Cologne under the supervision of Prof. Dr. Benjamin Rott. His research focuses on mathematical problem solving and teachers’ beliefs.
