He subsequently continued his career in Warsaw (2012), Bonn (2012–2015), and Bielefeld (2015–2020) before returning to Oxford where he joined the university's Mathematical Institute.
[1] He is known for formulating a mathematical theorem allowing for the recognition of spaces, which after minor modifications, behave like spacetime in Einstein's theory of relativity.
[4] In 2023, he became the co-recipient of the Frontiers of Science Award together with Marek Kaluba (Karlsruhe Institute of Technology) and Piotr W. Nowak (Polish Academy of Sciences) for their research in the field of algebraic and geometric topology.
The award was presented at the inaugural International Congress of Basic Science (ICBS) in Beijing.
[5] In September 2023 Kielak was awarded a Title of Distinction of Professor of Pure Mathematics by the University of Oxford.