K​ürşat Sözer

I am a Postdoctoral Fellow at the Department of Mathematics & Statistics in McMaster University. I am part of the Geometry & Topology group and my mentor is Ian Hambleton. In May 2020, I got my PhD at Indiana University Bloomington under the supervision of Vladimir Turaev. Before coming to McMaster, I spent one year at Universit​é de Lille and another year at EPFL as an OCHoTop postdoc.


My broad research interests include low dimensional topology, higher dimensional topology, and quantum algebra.

I am particularly interested in topological field theories, homotopy field theories, homotopy self-equivalences of manifolds, cobordism hypothesis, quantum invariants of low dimensional manifolds, Hopf algebras, fusion and modular categories, and crossed modules. 

Recently, I am interested in extensions of fusion categories, group of homotopy self-equivalences of high-dimensional manifolds, Yetter's invariant, and cohomology of crossed modules.

Papers and Preprints

  • I. Hambleton, K. Sözer, R. Sroka, The space of homotopy self-equivalences of a manifold: Homotopy groups, in preparation.
  • K. Sözer, A. Virelizier, Crossed extensions of graded fusion categories, in preparation.
  • K. Sözer, A. Virelizier, 3-dimensional cohomological HQFTs and twisted Yetter invariant, in preparation.
  • K. Sözer, Remarks on 2-dimensional extended HQFTs, in preparation.
  • K. Sözer, A. Virelizier, 3d TQFTs and 3-manifold invariants, to appear in the 2nd Edition of Encyclopedia of Mathematical Physics.
  • K. Sözer, A. Virelizier, Hopf crossed module (co)algebras, submitted, arXiv:2305.15485.
  • K. Sözer, A. Virelizier, Monoidal categories graded by crossed modules and 3-dimensional HQFTs, Advances in Mathematics, 428 (2023) 109155.
  • K. Sözer, Two-dimensional extended homotopy field theories, Algebraic & Geometric Topology, 23:9 (2023) 3909--3996.


During Fall 2023 semester, I am teaching Math-3T03 Inquiry in Topology. If you are student of the course, see the avenue to learn webpage for the details of the course.

See CV for the complete list of my teaching experiences. Some of them are as follows.

  • Math-3T03: Inquiry in Topology (lecturing), Fall 2023 (McMaster University).
  • ​Math-2ZZ3: Engineering Mathematics IV (lecturing), Winter 2023 (McMaster University). 
  • Math-3T03: Inquiry in Topology (lecturing), Fall 2022 (McMaster University). 
  • Math-110 (a): Advanced Linear Algebra, (assisting), Fall 2021 (EPFL).
  • M303: Linear Algebra (assisting), Spring 2020 (Indiana University).
  • M27: Precalculus with Trigonometry (lecturing), Fall 2019 (Indiana University).
  • M25: Precalculus (lecturing), Spring 2016 (Indiana University).
  • M311: Calculus 3 (recitation), Fall 2015, Fall 2016 (Indiana University).

Seminar organization

I am the organizer of McMaster Geometry and Topology seminar during Fall 2023 semester. The seminar calendar of McMaster University Department of Mathematics and Statistics can be reached at this link

Contact Info  

Department of Mathematics and Statistics McMaster University  
Office: HH303A  
Email: sozerk at mcmaster dot ca