Torisu's unknotting-number-one conjecture for three-branched Montesinos knots

Let KK be a Montesinos knot with three branches. Here M(0;(p,r),(q,s),(2mn±1,2n2))M(0; (p,r),(q,s),(2mn\pm 1, 2n^2)) denotes the Montesinos knot with the displayed parameters. Torisu's conjecture. The knot KK has unknotting number one if and only if

K=M(0;(p,r),(q,s),(2mn±1,2n2)),K=\mathcal{M}(0; (p,r),(q,s),(2mn\pm 1, 2n^2)),

where p,q,r,s,mp,q,r,s,m and nn are non-zero integers, mm and nn are coprime, and ps+rq=1ps+rq=1. This gives a conjectural classification of the three-branched Montesinos knots with unknotting number one; Montesinos knots with four or more branches are known not to have unknotting number one, while the three-branch case remains the subject of this conjectural list.

Sources & referencesView supporting material

Primary source

Duncan McCoy, “Alternating knots with unknotting number one”, arXiv:1312.1278 (2014).

Additional references

2 papers in this index state this conjecture (2011–2013). The statement above is taken from the most recent of them; the others are arXiv:1109.4560.

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