Twisted Alexander polynomials and incompressible surfaces given by ideal points

Abstract

We study incompressible surfaces constructed by Culler-Shalen theory in the context of twisted Alexander polynomials. For a $1$st cohomology class of a $3$-manifold the coefficients of twisted Alexander polynomials induce regular functions on the $SL_2(\mathbb{C})$-character variety. We prove that if an ideal point gives a Thurston norm minimizing non-separating surface dual to the cohomology class, then the regular function of the highest degree has a finite value at the ideal point.Comment: 10 pages, to appear in "The special issue for the 20th anniversary", the Journal of Mathematical Sciences, the University of Toky