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 Show summary

  We study the Whitehead torsion of inertial h-cobordisms, continuing an investigation started in [12]. Of particular interest is a nested sequence of subsets of the Whitehead group, and a number of examples are given to show that these subsets are all different in general. The main new results are Theorem 2.5, Theorem 2.6, Theorem 2.7. Proposition 5.2 is a partial correction to [12, Lemma 8.1]. © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

• 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. Full text in Research Archive
• 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. Full text in Research Archive
• 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. Full text in Research Archive
• 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 9780821848395. p. 189–202. Full text in Research Archive
• Jahren, Bjørn (2009). Pseudoisotopies and the Bökstedt trace. Geometriae Dedicata. ISSN 0046-5755. doi: 10.1007/s10711-009-9441-7. Full text in Research Archive
• Jahren, Bjørn & Kwasik, S (2006). Manifolds homotopy equivalent to RP4#RP4. Mathematical proceedings of the Cambridge Philosophical Society (Print). ISSN 0305-0041. 140. Full text in Research Archive
• Jahren, Bjørn (2003). Three-dimensional surgery theory, UNil-groups and the Borel conjecture. Topology. ISSN 0040-9383. 42, p. 1353–1369. Full text in Research Archive
• Jahren, Bjørn (1999). K-theory, flat bundles and the Borel classes. Fundamenta Mathematicae. ISSN 0016-2736. 161, p. 137–153. Full text in Research Archive 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 9780691157757. 192 p. Full text in Research Archive
• Baas, Nils A.; Friedlander, Eric M.; Jahren, Bjørn & Østvær, Paul Arne (2009). Algebraic Topology. The Abel Symposium 2007. Springer. ISBN 9783642011993. Full text in Research Archive
• Jahren, Bjørn (2006). Motivic Homotopy Theory. Springer. ISBN 9783540458951. 222 p. Full text in Research Archive

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• Jahren, Bjørn (2017). H-Cobordisms and stabilization of diffeomorphisms. Full text in Research Archive
• 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. Full text in Research Archive
• Jahren, Bjørn (2016). On the work of Eldar Straume on Transformation Groups. Full text in Research Archive
• Jahren, Bjørn (2015). Inertial and non-inertial h-cobordisms. Full text in Research Archive
• Jahren, Bjørn (2012). How different can h-cobordant manifolds be? Full text in Research Archive
• Jahren, Bjørn (2012). How different can h-cobordant manifolds be? Full text in Research Archive
• Jahren, Bjørn (2012). H-cobordant manifolds. Full text in Research Archive
• Jahren, Bjørn (2011). Relationships between h-cobordant manifolds. Full text in Research Archive
• Jahren, Bjørn (2011). Fra musikk til algebra og geometri. Full text in Research Archive
• Jahren, Bjørn (2011). Exotic structures on manifolds. Full text in Research Archive
• Jahren, Bjørn (2011). Eksotiske sfærer. Full text in Research Archive
• Jahren, Bjørn (2009). Litt om topologisk fikspunktteori. Full text in Research Archive
• Jahren, Bjørn (2008). Topological classification of free involutions on S^1xS^n. Full text in Research Archive
• Jahren, Bjørn (2008). Topological classification of free involutions on S^1xS^n. Full text in Research Archive
• Jahren, Bjørn (2008). Topological classification of free involutions on S^1xS^n. Full text in Research Archive
• Jahren, Bjørn (2007). Topological classification of free involutions on S1xSn. Full text in Research Archive
• Jahren, Bjørn (2007). Topological classification of free involutions on S1xSn. Full text in Research Archive
• Jahren, Bjørn (2006). Lefschetz-Nielsen teori og homotopi-fikspunkter. Full text in Research Archive
• Jahren, Bjørn (2006). Trace invariants for fixed and periodic points. Full text in Research Archive
• Jahren, Bjørn (2006). Manifolds homotopy equivalent to RP^4#RP^4. Full text in Research Archive
• Jahren, Bjørn (2006). Trace invariants for fixed and periodic points. Oberwolfach Reports. ISSN 1660-8933. Full text in Research Archive
• Jahren, Bjørn (2005). On manifolds homotopy equivalent to RP^4 x RP^4. Full text in Research Archive
• Jahren, Bjørn (2005). Topological classification of free involutions on S^1 x S^n. Full text in Research Archive
• Jahren, Bjørn (2005). On manifolds homotopy equivalent to RP^4#RP^4. Full text in Research Archive
• Jahren, Bjørn (2005). Some calculations of rational homotopy of diffeomorphism groups. Full text in Research Archive
• Jahren, Bjørn (2005). On topological mansilds doubly covered by S^1xS^n. Full text in Research Archive
• Jahren, Bjørn (2005). Fixpoints and homotopy fixpoint of maps. Full text in Research Archive
• Jahren, Bjørn (2005). Introduction to surgery theory. Full text in Research Archive
• Jahren, Bjørn (2005). Topological classification of free involutions of S^1xS^n. Full text in Research Archive
• Jahren, Bjørn (2005). Topological classification of free involutions on S^1xS^n. Full text in Research Archive
• Jahren, Bjørn (2005). Classification of free involutions on S^1xS^3. Full text in Research Archive
• Jahren, Bjørn (2005). Topological classifications of free involutions on S^1xS^n. Full text in Research Archive
• Jahren, Bjørn (2004). A homological formula for the Lefschetz-Reidemeister torsion. Full text in Research Archive
• Jahren, Bjørn (2004). Geometri og geometrier i dimensjon 3 (To foredrag). Full text in Research Archive
• Jahren, Bjørn (2004). Homotoy fixpoints and Nielsen-Lefschetz theory. Full text in Research Archive
• Jahren, Bjørn (2001). Problems and results in low-dimensional surgery. Full text in Research Archive
• Jahren, Bjørn (2001). On surgery in dimension 3. Full text in Research Archive
• Jahren, Bjørn (2001). 3-dimensional surgery, UNil-groups and the Borel conjecture. Full text in Research Archive
• Jahren, Bjørn (2001). On surgery in dimension 3. Full text in Research Archive
• Jahren, Bjørn (2000). Hvorfor er det så trangt i dimensjon 4? Full text in Research Archive
• Jahren, Bjørn (2000). Hvorfor er det så trangt i dimensjon 4? Full text in Research Archive
• Jahren, Bjørn (2000). Flat bundles and Borel classes in K-theory. Full text in Research Archive
• Jahren, Bjørn (2000). Kirurgiobstruksjonen i dimensjon 3. Full text in Research Archive
• Jahren, Bjørn (2000). Topology and geometry of 3-manifolds. Full text in Research Archive
• Jahren, Bjørn (2000). Hvorfor er det så trangt i dimensjon 4? Full text in Research Archive
• Jahren, Bjørn (2000). Mozart, menuetter og terningkast. [Radio]. "WOK" : NRK, P2. Full text in Research Archive
• Jahren, Bjørn (2000). Mozart, menuetter og terningkast. [Radio]. Metropol TV. Full text in Research Archive
• Jahren, Bjørn (2000). Flat bundles and Borel classes in K-theory. Full text in Research Archive
• Jahren, Bjørn (2000). Mozart, menuetter og terningkast. [Radio]. "Midt i musikken" : NRK radio, P2. Full text in Research Archive
• Jahren, Bjørn (2000). Mozart, menuetter og terningkast. [Radio]. Metropol TV. Full text in Research Archive
• Jahren, Bjørn (1999). 3-dimensional surgery and the Borel conjecture. Full text in Research Archive 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. Full text in Research Archive
• Jahren, Bjørn (2010). Supplementary notes for MAT4520, Spring 2010. Internt på kurssider. Full text in Research Archive
• Jahren, Bjørn (2007). geometric structures. Matematisk institutt, kurssidene til MAT4510. Full text in Research Archive
• Jahren, Bjørn & Kwasik, Slawomir (2006). Free involutions on S^1xS^n. Institut Mittag-Leffler. Full text in Research Archive
• Jahren, Bjørn; Rognes, John & Waldhausen, Friedhelm (2006). Spaces of PL manifolds and categories of simple maps. Institut Mittag-Leffler. Full text in Research Archive
• Jahren, Bjørn & Kwasik, Slawomir (2000). 3-DIMENSIONAL SURGERY THEORY, UNiL-GROUPS AND THE BOREL CONJECTURE. Universitetet i Oslo. Full text in Research Archive
• Jahren, Bjørn & Kwasik, Slawomir (1999). 3-dimensional surgery, UNil and the Borel conjecture. Full text in Research Archive
• Jahren, Bjørn (1995). IGUSA'S EXACT SEQUENCE AND THE BÖKSTEDT TRACE. Universitetet i Oslo. Full text in Research Archive
• Jahren, Bjørn (1993). K-THEORY, FLAT BUNDLES AND THE BOREL CLASSES. Universitetet i Oslo. Full text in Research Archive
• Dundas, Bjørn Ian & Jahren, Bjørn (1991). The K-Theories of Gersten/Swan and Waldhausen Agree on most Simplicial Rings. Universitetet i Oslo. Full text in Research Archive
• Jahren, Bjørn (1973). SMOOTHING THEORY AND TOPOLOGY OF PL/O. Universitetet i Oslo. Full text in Research Archive

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