Reidemeister torsion is a combinatorial invariant, famous among other things for distinguishing finite quotients of the sphere S^3, the lenticular spaces, which have the same homotopy type but which are not homeomorphic. The study of the torsion for more general 3-manifold (such as knot exteriors) is closely related to the study of their character varieties: these are algebraic varieties whose points are conjugacy classes of representations of fundamental groups. I will review some results I obtained in my thesis on this subject, and will discuss a recent result in collaboration with Ryoto Tange, Anh Tran and Jun Ueki, where we study the divisor induced by the torsion on these varieties.<\/p>\n","protected":false},"excerpt":{"rendered":"
Reidemeister torsion is a combinatorial invariant, famous among other things for distinguishing finite quotients of the sphere S^3, the lenticular…<\/p>\n