Census L-space knots are braid positive, except for one that is not

被引:2
|
作者
Baker, Kenneth L. [1 ]
Kegel, Marc [2 ]
机构
[1] Univ Miami, Dept Math, Coral Gables, FL 33146 USA
[2] Humboldt Univ, Math Inst, Berlin, Germany
来源
ALGEBRAIC AND GEOMETRIC TOPOLOGY | 2024年 / 24卷 / 01期
关键词
FLOER HOMOLOGY;
D O I
10.2140/agt.2024.24.569
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
We exhibit braid positive presentations for all L-space knots in the SnapPy census except one, which is not braid positive. The normalized HOMFLY polynomial of o9_30634, when suitably normalized, is not positive, failing a condition of Ito for braid positive knots. We generalize this knot to a 1-parameter family of hyperbolic L-space knots that may not be braid positive. Nevertheless, as pointed out by Teragaito, this family yields the first examples of hyperbolic L-space knots whose formal semigroups are actual semigroups, answering a question of Wang. Further, the roots of the Alexander polynomials of these knots are all roots of unity, disproving a conjecture of Li and Ni.
引用
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页码:569 / 586
页数:21
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