×

The Jones slopes of a knot. (English) Zbl 1228.57004

This paper tries to give a partial topological interpretation to the Jones polynomial. As the author remarks, this topological/geometrical meaning is better understood when the Jones polynomial is viewed as part of the coloured Jones function \(\{ J_K(n,q) \} _n\), and one looks at some suitable limits of this sequence.
For each natural number \(n\), the coloured Jones function of a knot \(K\) is given by a Laurent polynomial \(J_K(n,q)\) in \(q\). For \(n=2\) we recover the classical Jones polynomial. Let \(\delta _K^*(n)\) and \(\delta_K(n)\) be respectively the lowest and the highest degrees of this polynomial. By definition, the Jones slopes of \(K\) are the cluster points (limit points of a subsequence) of the sequences \(\{ \frac{4}{n^2}\delta_K^*(n)\}\) and \(\{ \frac{4}{n^2}\delta_K(n)\}\).
Let \(M_K\) be the exterior of a knot \(K\). Each properly embedded, essential (incompressible and boundary incompressible) orientable surface \(S\) in \(M_K\) determines some boundary curves in the torus \(T=\partial M_K\). Each of these boundary curves goes round \(a\) meridians and \(b\) longitudes of \(T\). By definition \(a/b \in \mathbb Q \cup \infty\) is said to be a boundary slope of the knot \(K\). In [Pac. J. Math. 99, 373–377 (1982; Zbl 0502.57005)], A. E. Hatcher proved that every knot has finitely many boundary slopes.
The author conjectures that, for any knot, its Jones slopes are always boundary slopes. In the paper the conjecture is proved for alternating knots, knots with at most nine crossings, torus knots and \((-2,3,n)\) pretzel knots.
Specifically, in the case of an alternating knot \(K\) with \(c^+\) positive crossings and \(c^-\) negative crossings in a reduced planar projection of \(K\), Theorem 2 states that the Jones slopes are \(-2c^-\) and \(2c^+\), and these are the boundary slopes of \(K\) that correspond to the two checkerboard surfaces of \(K\) (doubled, if needed, to make them orientable).
A relevant fact when studying the Jones slopes is that the coloured Jones function is holonomic (i.e., it satisfies a linear recursive relation). This implies (Theorem 1) that the sequence of degrees \(\{ \delta_K(n) \}\) is a quadratic quasi-polynomial for large \(n\). The Jones period of a knot is defined as the period of this quasi-polynomial (for the definition of the period of a quasi-polynomial see Definition 1.5), and it is seen to be one for every alternating knot. For knots with a non-integral Jones slope, this period is greater that one.
We remark that, in [D. Futer, E. Kalfagianni and J. S. Purcell, Proc. Am. Math. Soc. 139, No. 5, 1889–1896 (2011; Zbl 1232.57007)], the conjecture has also been proved for adequate knots.

MSC:

57M25 Knots and links in the \(3\)-sphere (MSC2010)
57N10 Topology of general \(3\)-manifolds (MSC2010)

Software:

Regina; Knot Atlas

References:

[1] Bar-Natan, The knot atlas. · Zbl 0898.57001
[2] D. Bar-Natan and S. Garoufalidis, On the Melvin-Morton-Rozansky conjecture. Invent. Math. 125 (1996), 103-133. · Zbl 0855.57004 · doi:10.1007/s002220050070
[3] D. Bar-Natan and R. Lawrence, A rational surgery formula for the LMO invariant. Israel J. Math. 140 (2004), 29-60. · Zbl 1062.57015 · doi:10.1007/BF02786626
[4] A. Barvinok and J. E. Pommersheim, An algorithmic theory of lattice points in polyhedra. In New perspectives in algebraic combinatorics (Berkeley, CA, 1996- 97), Math. Sci. Res. Inst. Publ. 38, Cambridge University Press, Cambridge 1999, 91-147. · Zbl 0940.05004
[5] M. Beck and S. Robins, Computing the continuous discretely . Undergrad. Texts Math., Springer-Verlag, New York 2007. · Zbl 1114.52013 · doi:10.1007/978-0-387-46112-0
[6] M. Brion and M. Vergne, Lattice points in simple polytopes. J. Amer. Math. Soc. 10 (1997), 371-392. · Zbl 0871.52009 · doi:10.1090/S0894-0347-97-00229-4
[7] B. A. Burton, Introducing Regina, the 3-manifold topology software. Experiment. Math. 13 (2004), 267-272. · Zbl 1090.57003 · doi:10.1080/10586458.2004.10504538
[8] S. Carter, D. E. Flath, and M. Saito, The classical and quantum 6j -symbols. Math. Notes 43, Princeton University Press, Princeton, NJ, 1995. · Zbl 0851.17001
[9] D. Cooper, M. Culler, H. Gillet, D. D. Long, and P. B. Shalen, Plane curves as- sociated to character varieties of 3-manifolds. Invent. Math. 118 (1994), 47-84. · Zbl 0842.57013 · doi:10.1007/BF01231526
[10] F. Costantino, Integrality of Kauffman brackets of trivalent graphs. Preprint 2009. · Zbl 1298.57009 · doi:10.4171/QT/49
[11] M. Culler, Tables of A-polynomials. Available at
[12] M. Culler, C. M. Gordon, J. Luecke, and P. B. Shalen, Dehn surgery on knots. Ann. of Math. (2) 125 (1987), 237-300. · Zbl 0633.57006 · doi:10.2307/1971311
[13] M. Culler and P. B. Shalen, Bounded, separating, incompressible surfaces in knot manifolds. Invent. Math. 75 (1984), 537-545. · Zbl 0542.57011 · doi:10.1007/BF01388642
[14] C. L. Curtis and S. Taylor, The Jones polynomial and boundary slopes of alternating knots. Preprint 2009, · Zbl 1238.57009 · doi:10.1142/S0218216511009194
[15] N. M. Dunfield, A table of boundary slopes of Montesinos knots. Topology 40 (2001), 309-315. · Zbl 0967.57014 · doi:10.1016/S0040-9383(99)00064-6
[16] N. M. Dunfield and S. Garoufalidis, Boundary slopes of 1-cusped manifolds. Preprint 2010.
[17] E. Ehrhart, Sur les polyèdres homothétiques bordés à n dimensions. C. R. Acad. Sci. Paris 254 (1962), 988-990. · Zbl 0100.27602
[18] D. Futer, E. Kalfagianni, and J. S. Purcell, Dehn filling, volume, and the Jones poly- nomial. J. Differential Geom. 78 (2008), 429-464. · Zbl 1144.57014
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.