Bjørn Jahren

• Hausmann, Jean-Claude & Jahren, Bjørn (2019). A simplification problem in manifold topology. L'Enseignement mathématique (LEM). ISSN 0013-8584. 64(1/2), p. 207–248. doi: 10.4171/LEM/64-1/2-8. Full text in Research Archive
• Jahren, Bjørn & Kwasik, Slawomir (2018). Whitehead torsion of inertial h-cobordisms. Topology and its Applications. ISSN 0166-8641. 249, p. 150–159. doi: 10.1016/j.topol.2018.09.013. Full text in Research Archive
• Jahren, Bjørn & Sławomir, Kwasik (2015). How different can h-cobordant manifolds be? Bulletin of the London Mathematical Society. ISSN 0024-6093. 47(4), p. 617–630. doi: 10.1112/blms/bdv039.
• Jahren, Bjørn & Kwasik, Slawomir (2011). Free involutions on S-1 x S-n. Mathematische Annalen. ISSN 0025-5831. 351(2), p. 281–303. doi: 10.1007/s00208-010-0599-y.
• Jahren, Bjørn (2010). Pseudoisotopies and the Bokstedt trace. Geometriae Dedicata. ISSN 0046-5755. 148(1), p. 245–261. doi: 10.1007/s10711-009-9441-7.
• Jahren, Bjørn (2009). Involutions on the rational K -theory of group rings of finite groups, Alpine Perspectives on Algebraic Topology. American Mathematical Society (AMS). ISSN 978-0-8218-4839-5. p. 189–202.
• Jahren, Bjørn (2009). Pseudoisotopies and the Bökstedt trace. Geometriae Dedicata. ISSN 0046-5755. doi: 10.1007/s10711-009-9441-7.
• Jahren, Bjørn & Kwasik, S (2006). Manifolds homotopy equivalent to RP4#RP4. Mathematical proceedings of the Cambridge Philosophical Society (Print). ISSN 0305-0041. 140.
• Jahren, Bjørn (2003). Three-dimensional surgery theory, UNil-groups and the Borel conjecture. Topology. ISSN 0040-9383. 42, p. 1353–1369.
• Jahren, Bjørn (1999). K-theory, flat bundles and the Borel classes. Fundamenta Mathematicae. ISSN 0016-2736. 161, p. 137–153. Show summary

  Using Hausmann and Vogel's homology sphere bundle interpretation of algebraic K-theory, we construct K-theory invariants by a theory of characteristic classes for flat bundles. It is shown that the Borel classes are detected this way, as well as the rational K-theory of integer group rings of finite groups.

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• Rognes, John; Jahren, Bjørn & Waldhausen, Friedhelm (2013). Spaces of PL Manifolds and Categories of Simple Maps. Princeton University Press. ISBN 978-0-691-15775-7. 192 p.
• Baas, Nils A.; Friedlander, Eric M.; Jahren, Bjørn & Østvær, Paul Arne (2009). Algebraic Topology. The Abel Symposium 2007. Springer. ISBN 978-3-642-01199-3.
• Jahren, Bjørn (2006). Motivic Homotopy Theory. Springer. ISBN 3-540-45895-6. 222 p.

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• Jahren, Bjørn (2017). H-Cobordisms and stabilization of diffeomorphisms.
• Jahren, Bjørn (2016). On the work of Eldar Straume on Transformation Groups.
• Nerland, Stener; Jørgensen, Kjetil Nordbø; Jahren, Bjørn; Melle, Ingrid; Andreassen, Ole Andreas & Agartz, Ingrid (2016). A Topological Characterisation of Cortical Folding in Schizophrenia and Bipolar Disorder.
• Jahren, Bjørn (2015). Inertial and non-inertial h-cobordisms.
• Jahren, Bjørn (2012). How different can h-cobordant manifolds be?
• Jahren, Bjørn (2012). How different can h-cobordant manifolds be?
• Jahren, Bjørn (2012). H-cobordant manifolds.
• Jahren, Bjørn (2011). Relationships between h-cobordant manifolds.
• Jahren, Bjørn (2011). Fra musikk til algebra og geometri.
• Jahren, Bjørn (2011). Exotic structures on manifolds.
• Jahren, Bjørn (2011). Eksotiske sfærer.
• Jahren, Bjørn (2009). Litt om topologisk fikspunktteori.
• Jahren, Bjørn (2008). Topological classification of free involutions on S^1xS^n.
• Jahren, Bjørn (2008). Topological classification of free involutions on S^1xS^n.
• Jahren, Bjørn (2008). Topological classification of free involutions on S^1xS^n.
• Jahren, Bjørn (2007). Topological classification of free involutions on S1xSn.
• Jahren, Bjørn (2007). Topological classification of free involutions on S1xSn.
• Jahren, Bjørn (2006). Trace invariants for fixed and periodic points. Oberwolfach Reports. ISSN 1660-8933.
• Jahren, Bjørn (2006). Lefschetz-Nielsen teori og homotopi-fikspunkter.
• Jahren, Bjørn (2006). Trace invariants for fixed and periodic points.
• Jahren, Bjørn (2005). Some calculations of rational homotopy of diffeomorphism groups.
• Jahren, Bjørn (2005). Classification of free involutions on S^1xS^3.
• Jahren, Bjørn (2005). Fixpoints and homotopy fixpoint of maps.
• Jahren, Bjørn (2005). Introduction to surgery theory.
• Jahren, Bjørn (2005). On topological mansilds doubly covered by S^1xS^n.
• Jahren, Bjørn (2005). Topological classifications of free involutions on S^1xS^n.
• Jahren, Bjørn (2005). Topological classification of free involutions of S^1xS^n.
• Jahren, Bjørn (2005). Topological classification of free involutions on S^1xS^n.
• Jahren, Bjørn (2005). Topological classification of free involutions on S^1 x S^n.
• Jahren, Bjørn (2005). On manifolds homotopy equivalent to RP^4 x RP^4.
• Jahren, Bjørn (2005). On manifolds homotopy equivalent to RP^4#RP^4.
• Jahren, Bjørn (2004). Geometri og geometrier i dimensjon 3 (To foredrag).
• Jahren, Bjørn (2004). A homological formula for the Lefschetz-Reidemeister torsion.
• Jahren, Bjørn (2004). Homotoy fixpoints and Nielsen-Lefschetz theory.
• Jahren, Bjørn (2004). Manifolds homotopy equivalent to RP^4#RP^4.
• Jahren, Bjørn (2001). 3-dimensional surgery, UNil-groups and the Borel conjecture.
• Jahren, Bjørn (2001). Problems and results in low-dimensional surgery.
• Jahren, Bjørn (2001). On surgery in dimension 3.
• Jahren, Bjørn (2001). On surgery in dimension 3.
• Jahren, Bjørn (2000). Mozart, menuetter og terningkast. [Radio]. "Midt i musikken" : NRK radio, P2.
• Jahren, Bjørn (2000). Mozart, menuetter og terningkast. [Radio]. "WOK" : NRK, P2.
• Jahren, Bjørn (2000). Mozart, menuetter og terningkast. [Radio]. Metropol TV.
• Jahren, Bjørn (2000). Mozart, menuetter og terningkast. [Radio]. Metropol TV.
• Jahren, Bjørn (2000). Flat bundles and Borel classes in K-theory.
• Jahren, Bjørn (2000). Hvorfor er det så trangt i dimensjon 4?
• Jahren, Bjørn (2000). Hvorfor er det så trangt i dimensjon 4?
• Jahren, Bjørn (2000). Hvorfor er det så trangt i dimensjon 4?
• Jahren, Bjørn (2000). Kirurgiobstruksjonen i dimensjon 3.
• Jahren, Bjørn (2000). Flat bundles and Borel classes in K-theory.
• Jahren, Bjørn (2000). Topology and geometry of 3-manifolds.
• Jahren, Bjørn (1999). 3-dimensional surgery and the Borel conjecture. Show summary

  The Borel conjecture asserts that closed aspherical manifolds are determined up to homeomorphism by their fundamental groups. The general conjecture is still open, but it has been proved for classes of manifolds satisfying certain geometric properties. Using surgery theory in dimension three and stabilizing, we show that the assertion holds for new classes of manifolds, and we also discuss the possibilities of counterexamples to Borel's conjecture. This is joint work with Slawomir Kwasik, Tulane University.

• Jahren, Bjørn (2011). Geometric Structures in Dimension two. Nettsidene til kurset MAT4510.
• Jahren, Bjørn (2010). Supplementary notes for MAT4520, Spring 2010. Internt på kurssider.
• Jahren, Bjørn (2007). geometric structures. Matematisk institutt, kurssidene til MAT4510.
• Jahren, Bjørn & Kwasik, Slawomir (2006). Free involutions on S^1xS^n. Institut Mittag-Leffler.
• Jahren, Bjørn; Rognes, John & Waldhausen, Friedhelm (2006). Spaces of PL manifolds and categories of simple maps. Institut Mittag-Leffler.
• Jahren, Bjørn & Kwasik, Slawomir (1999). 3-dimensional surgery, UNil and the Borel conjecture.

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