Seifert vs. slice genera of knots in twist families and a characterization of braid axes
Twisting a knot K in S3 along a disjoint unknot c produces a twist family of knots {Kn} indexed by the integers. We prove that if the ratio of the Seifert genus to the slice genus for knots in a twist family limits to 1, then the winding number of K about c equals either zero or the wrapping number....
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Veröffentlicht in: | Proceedings of the London Mathematical Society 2019-12, Vol.119 (6), p.1493-1530, Article 1493 |
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Sprache: | eng |
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Zusammenfassung: | Twisting a knot K in S3 along a disjoint unknot c produces a twist family of knots {Kn} indexed by the integers. We prove that if the ratio of the Seifert genus to the slice genus for knots in a twist family limits to 1, then the winding number of K about c equals either zero or the wrapping number. As a key application, if {Kn} or the mirror twist family {Kn¯} contains infinitely many tight fibered knots, then the latter must occur. This leads to the characterization that c is a braid axis of K if and only if both {Kn} and {Kn¯} each contain infinitely many tight fibered knots. We also give a necessary and sufficient condition for {Kn} to contain infinitely many L‐space knots, and apply the characterization to prove that satellite L‐space knots have braided patterns, which answers a question of both Baker–Moore and Hom in the positive. This result also implies an absence of essential Conway spheres for satellite L‐space knots, which gives a partial answer to a conjecture of Lidman–Moore. |
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ISSN: | 0024-6115 1460-244X |
DOI: | 10.1112/plms.12274 |