{ "id": "2011.12287", "version": "v1", "published": "2020-11-24T18:57:29.000Z", "updated": "2020-11-24T18:57:29.000Z", "title": "The cobordism distance between a knot and its reverse", "authors": [ "Charles Livingston" ], "comment": "6 pages, 2 figures", "categories": [ "math.GT" ], "abstract": "The cobordism distance between knots, d(K,J), equals the four-genus g_4(K # -J). We consider d(K,K^r), where K^r is the reverse of K. It is elementary that 0 \\le d(K,K^r) \\le 2g_4(K) and it is known that there are knots K for which d(K,K^r) is arbitrarily large. Here it is shown that for any knot for which g_4(K) = g_3(K) (such as non-slice knots with g_3(K) = 1 or strongly quasi-positive knots), one has that d(K,K^r) is strictly less that twice g_4(K). It is shown that for arbitrary positive g, there exist knots for which d(K,K^r) = g = g_4(K). There are no known examples for which d(K,K^r) > g_4(K).", "revisions": [ { "version": "v1", "updated": "2020-11-24T18:57:29.000Z" } ], "analyses": { "subjects": [ "57K10" ], "keywords": [ "cobordism distance", "non-slice knots", "four-genus", "elementary" ], "note": { "typesetting": "TeX", "pages": 6, "language": "en", "license": "arXiv", "status": "editable" } } }