{ "id": "1106.1259", "version": "v2", "published": "2011-06-07T05:46:43.000Z", "updated": "2011-06-08T01:08:55.000Z", "title": "The canonical genus for Whitehead doubles of a family of alternating knots", "authors": [ "Hee Jeong Jang", "Sang Youl Lee" ], "comment": "33 pages, 27 figures", "categories": [ "math.GT" ], "abstract": "For any given integer $r \\geq 1$ and a quasitoric braid $\\beta_r=(\\sigma_r^{-\\epsilon} \\sigma_{r-1}^{\\epsilon}...$ $ \\sigma_{1}^{(-1)^{r}\\epsilon})^3$ with $\\epsilon=\\pm 1$, we prove that the maximum degree in $z$ of the HOMFLYPT polynomial $P_{W_2(\\hat\\beta_r)}(v,z)$ of the doubled link $W_2(\\hat\\beta_r)$ of the closure $\\hat\\beta_r$ is equal to $6r-1$. As an application, we give a family $\\mathcal K^3$ of alternating knots, including $(2,n)$ torus knots, 2-bridge knots and alternating pretzel knots as its subfamilies, such that the minimal crossing number of any alternating knot in $\\mathcal K^3$ coincides with the canonical genus of its Whitehead double. Consequently, we give a new family $\\mathcal K^3$ of alternating knots for which Tripp's conjecture holds.", "revisions": [ { "version": "v2", "updated": "2011-06-08T01:08:55.000Z" } ], "analyses": { "subjects": [ "57M25", "57M27" ], "keywords": [ "alternating knot", "canonical genus", "whitehead double", "tripps conjecture holds", "minimal crossing number" ], "note": { "typesetting": "TeX", "pages": 33, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1106.1259J" } } }