Representations of knot groups into and twisted Alexander polynomials
arXiv:1407.3705 · doi:10.2140/pjm.2015.277.313
Abstract
Let be the fundamental group of the exterior of a knot in the three-sphere. We study deformations of representations of into which are the sum of two irreducible representations. For such representations we give a necessary condition, in terms of the twisted Alexander polynomial, for the existence of irreducible deformations. We also give a more restrictive sufficient condition for the existence of irreducible deformations. We also prove a duality theorem for twisted Alexander polynomials and we describe the local structure of the representation and character varieties.