Prof. Dr. Jens Hornbostel

Former Bonn Junior Fellow
Current position: Professor (W3), University of Wuppertal

E-mail: hornbostel(at)
Institute: Mathematical Institute

Academic Career


Thèse de doctorat, Paris Diderot University (Paris 7), France

2001 - 2002

Postdoc, Northwestern University, Evanston, IL, USA

2002 - 2007

Assistant Professor, University of Regensburg

2007 - 2010

Professor (W2, Bonn Junior Fellow), University of Bonn


Professor (W2), University of Bielefeld

Since 2010

Professor (W3), University of Wuppertal

Research Profile

My main research interests are related to algebraic K-theory and motivic homotopy theory in the sense of Morel-Voevodsky. I am in particular interested in generalized algebraic cohomology theories representable in the motivic stable homotopy category, e.g. Hermitian K-theory, Witt groups and algebraic cobordism.

Research Projects and Activities

Georgian-German Algebra and Topology Partner Group (founded by the Volkswagenstiftung)

Workshop “Geometric Aspects of Motivic Homotopy Theory”
Organizer, Bonn, 2010 (with Jardine, Levine)

Contribution to Research Areas

Former Research Area E
Together with Calmes ([1] and an article which has just appeared [2]), we established push-forward morphisms for Witt groups with respect to proper morphisms, along with basic properties and some applications. In a preprint with my postdoc Kirichenko (to appear in Crelle) we provide a Schubert calculus for algebraic cobordism of complete flag varieties. In another recent preprint, we give a proof of Lurie's theorem that K-theory classifies orientations of the derived multiplicative group, using the language of model categories and symmetric spectra. We then prove a motivic generalization of this theorem involving motivic symmetric spectra and algebraic K-theory.

Selected Publications

[1] Baptiste Calmès, Jens Hornbostel
Tensor-triangulated categories and dualities
Theory Appl. Categ. , 22: : No. 6, 136--200

Publication List

Supervised Theses

  • Diplom theses: 5, currently 3
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