{ "id": "1302.1631", "version": "v2", "published": "2013-02-07T02:39:39.000Z", "updated": "2013-09-04T00:25:38.000Z", "title": "On the twisted Alexander polynomial for representations into SL_2(C)", "authors": [ "Anh T. Tran" ], "comment": "Minor changes. To appear in Journal of Knot Theory and Its Ramifications", "categories": [ "math.GT" ], "abstract": "We study the twisted Alexander polynomial $\\Delta_{K,\\rho}$ of a knot $K$ associated to a non-abelian representation $\\rho$ of the knot group into $SL_2(\\BC)$. It is known for every knot $K$ that if $K$ is fibered, then for every non-abelian representation, $\\Delta_{K,\\rho}$ is monic and has degree $4g(K)-2$ where $g(K)$ is the genus of $K$. Kim and Morifuji recently proved the converse for 2-bridge knots. In fact they proved a stronger result: if a 2-bridge knot $K$ is non-fibered, then all but finitely many non-abelian representations on some component have $\\Delta_{K,\\rho}$ non-monic and degree $4g(K)-2$. In this paper, we consider two special families of non-fibered 2-bridge knots including twist knots. For these families, we calculate the number of non-abelian representations where $\\Delta_{K,\\rho}$ is monic and calculate the number of non-abelian representations where the degree of $\\Delta_{K,\\rho}$ is less than $4g(K)-2$.", "revisions": [ { "version": "v2", "updated": "2013-09-04T00:25:38.000Z" } ], "analyses": { "subjects": [ "57M27" ], "keywords": [ "twisted alexander polynomial", "non-abelian representation", "twist knots", "knot group", "special families" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1302.1631T" } } }