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Mathematician and Spinoza Prize winner Prof. Ieke Moerdijk began work as a ľ�ϸ���Ӱ�� Professor at Utrecht ľ�ϸ���Ӱ�� on 1 January. He experienced his return to the Uithof as ‘familiar on the one hand, and refreshing on the other’. He is looking forward to working with the new young colleagues that Mathematics has recruited over the past few years, as well as his ambition to bring together different users and uses of mathematics across the university.

In the first week of January, Prof. Moerdijk was still surrounded by moving boxes holding his books and papers. His new office is on the top floor of the Freudenthal building, two floors higher than when he left for Radboud ľ�ϸ���Ӱ�� Nijmegen four years ago. “I’ve clearly come up in the world”, he jokes. He wished to emphasise that he enjoyed working in Nijmegen. “But it is a great honour to be appointed as a ľ�ϸ���Ӱ�� Professor. It is only a position like this that provides the freedom for all my activities."

Breadth across the university

When looking at his curriculum, his interest in the breadth of Mathematics and in bringing people together immediately leap out at the reader. Moerdijk combined studies in Philosophy and General Linguistics with his studies in Mathematics. In his doctoral research, he combined topology, which is part of geometry, with mathematical logic and became one of the pioneers in the field of Topological Logic. He researched connections between algebra and set theory, and algebra and topology. He also received the Descartes-Huygens Prize for his contributions to the scientific collaboration between France and The Netherlands. And now he hopes to connect the applications of mathematics across the faculties at Utrecht ľ�ϸ���Ӱ��.

Raise awareness of Mathematics

“Mathematics is used in a large number of disciplines, but it is usually relegated to the background. Mathematicians are often unaware of how and where they can help their fellow researchers. And researchers from different faculties may need the same mathematical tools and techniques, without knowing it. It would be great if there were more awareness of these issues within the university, across the borders of the faculties and disciplines. I hope to contribute to bringing this about.”

As a scientist, I need the contact with young people: I enjoy stimulating young students, and being inspired by talented PhD students and postdocs.

Utrecht Geometry Centre

In addition to the tasks above, he plans on continuing his Spinoza research in topology and mathematical logic. “The Utrecht Geometry Centre does a lot of work on geometry and topology, and I think that the scale of the centre’s work and its reputation will be a good foundation for me to build on. As a scientist, I need the contact with young people: I enjoy stimulating young students, and being inspired  by talented PhD students and postdocs. At the same time, as a ľ�ϸ���Ӱ�� Professor and with the support and resources that come with the Spinoza Prize, I hope to promote the Geometry Centre internationally, for example by giving courses for international students.”

Tree structures

Topology is a mathematical theory of shapes, and how they can interact and be deformed. “How can you determine whether one figure is a deformation of another using mathematics? And what happens to simple algebraic equations, such as the associative law a+(b+c) = (a+b)+c, which may hold for points or parts of a shape, after certain deformations?" , Moerdijk gives as an example. In many cases, such a simple law deforms into an infinite system of equations, and the problem is how to describe and control such a system. Together with several of his colleagues, over the past few years Moerdijk has shown that these equations can form intricate tree-like structures. “This results in a beautiful geometry for those structures, which I would love to explain in a book. I hope to be able to find the time to do that over the next few years.”

Ieke Moerdijk

Ieke Moerdijk (1958) studied Mathematics, Philosophy and General Linguistics at the ľ�ϸ���Ӱ�� of Amsterdam and earned his PhD cum laude in 1985 with his dissertation ‘Topics in intuitionism and topos theory’. After that, he worked as a postdoc at the universities of Chicago and Cambridge. From 1988 to 2011, he was affiliated with Utrecht ľ�ϸ���Ӱ��, where he was appointed as Endowed Professor in 1996 and Full Professor in 2002. From 2011 to 2015, he served as Professor of Algebra and Topology at Radboud ľ�ϸ���Ӱ�� in Nijmegen.

Moerdijk occupied several visiting professorships, including at St. John’s College in Cambridge, McGill ľ�ϸ���Ӱ�� in Montreal, the ľ�ϸ���Ӱ�� of Sydney and the ľ�ϸ���Ӱ�� of Aarhus. In 2006, he was elected Member of the KNAW, and is currently the Chairman of the Ammodo KNAW Awards for the Natural Sciences advisory committee. In 2015, he was one of the committee members who was asked by Minister Jet Bussemaker to elaborate the Netherlands Mathematics Platform vision document into the Delta Plan for Dutch Mathematics.

In 2012, he received both the  for his contributions to Franco-Dutch scientific cooperation, as well as the Netherlands’ most prestigious academic award, the . In 2014, he was elected to the exclusive .

In 1992, he wrote the textbook Sheaves in Geometry and Logic. A First Introduction to topos theory together with the American mathematician Saunders Mac Lane.