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A characterization of quasipositive two-bridge knots. (English) Zbl 07844493

Summary: We prove a simple necessary and sufficient condition for a two-bridge knot \(K(p,q)\) to be quasipositive, based on the continued fraction expansion of \(p/q\). As an application, coupled with some classification results in contact and symplectic topology, we give a new proof of the fact that smoothly slice two-bridge knots are non-quasipositive. Another proof of this fact using methods within the scope of knot theory is presented in Appendix A, by Stepan Orevkov.

MSC:

57K10 Knot theory
57K33 Contact structures in 3 dimensions
57K43 Symplectic structures in 4 dimensions

References:

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