English

More 1-cocycles for classical knots

Geometric Topology 2021-04-07 v5

Abstract

Let MregM^{reg} be the topological moduli space of long knots up to regular isotopy, and for any natural number n>1n > 1 let MnregM^{reg}_n be the moduli space of all n-cables of framed long knots which are twisted by a string link to a knot in the solid torus V3V^3 . We upgrade the Vassiliev invariant v2v_2 of a knot to an integer valued combinatorial 1-cocycle for MnregM^{reg}_n by a very simple formula. This 1-cocycle depends on a natural number aZH1(V3;Z)a \in \mathbb{Z}\cong H_1(V^3;\mathbb{Z}) with 0<a<n0<a<n as a parameter and we obtain a polynomial-valued 1-cocycle by taking the Lagrange interpolation polynomial with respect to the parameter. We show that it induces a non-trivial pairing on H0(Mnreg)×H0(Mreg)H_0(M^{reg}_n) \times H_0(M^{reg}) already for n=2n=2.

Keywords

Cite

@article{arxiv.2004.04624,
  title  = {More 1-cocycles for classical knots},
  author = {Thomas Fiedler},
  journal= {arXiv preprint arXiv:2004.04624},
  year   = {2021}
}

Comments

69 pages, 56 figures, final version which includes (without proofs) the lift of the whole Conway polynomial to a non-trivial combinatorial 1-cocycle

R2 v1 2026-06-23T14:45:47.495Z