Erratum to Profinite rigidity for twisted Alexander polynomials (J. reine angew. Math. 771 (2021), 171–192)

We clarify the definition of the divisorial hull and recollect some basic facts. Then we correct Lemma 4.2 and Theorem 11.2 (1)–(2) in the original article.

Homotopy ribbon concordance and Alexander polynomials

We show that if a link J in the 3-sphere is homotopy ribbon concordant to a link L, then the Alexander polynomial of L divides the Alexander polynomial of J.

Profinite rigidity for twisted Alexander polynomials

We formulate and prove a profinite rigidity theorem for the twisted Alexander polynomials up to several types of finite ambiguity. We also establish torsion growth formulas of the twisted homology groups in a {{\mathbb{Z}}}-cover of a 3-manifold with use of Mahler measures. We examine several examples associated to Riley’s parabolic representations of two-bridge knot groups and give a remark on hyperbolic volumes.

Twisted Alexander polynomials of torus links

In this paper, we give an explicit formula for the twisted Alexander polynomial of any torus link and show that it is a locally constant function on the [Formula: see text]-character variety. We also discuss similar things for the higher-dimensional twisted Alexander polynomial and the Reidemeister torsion.

Stable Alexander polynomials of arborescent links

We study the zeros of Alexander polynomials of three classes of arborescent links. In the first class, the zeros are real (and negative) or modulus one. In the second class, the zeros are real (and positive). In the third class, the zeros are real or modulus one. For this purpose, we modify their Alexander polynomials into other real polynomials, with only real zeros, and use the property that two such polynomials have interlacing real zeros.

A Fox–Milnor theorem for knots in a thickened surface

A knot in a thickened surface [Formula: see text] is a smooth embedding [Formula: see text], where [Formula: see text] is a closed, connected, orientable surface. There is a bijective correspondence between knots in [Formula: see text] and knots in [Formula: see text], so one can view the study of knots in thickened surfaces as an extension of classical knot theory. An immediate question is if other classical definitions, concepts, and results extend or generalize to the study of knots in a thickened surface. One such famous result is the Fox–Milnor Theorem, which relates the Alexander polynomials of concordant knots. We prove a Fox–Milnor Theorem for concordant knots in a thickened surface by using Milnor torsion.