English
Related papers

Related papers: Some remarks on the chord index

200 papers

In this paper we study the chord index of virtual knots, which can be thought of as an extension of the chord parity. We show how to use the chord index to define finite type invariants of virtual knots. The notions of indexed Jones…

Geometric Topology · Mathematics 2026-05-26 Zhiyun Cheng

A weak chord index $Ind'$ is constructed for self crossing points of virtual links. Then a new writhe polynomial $W$ of virtual links is defined by using $Ind'$. $W$ is a generalization of writhe polynomial defined in [6]. Based on $W$,…

Geometric Topology · Mathematics 2018-12-14 Mengjian Xu

The motivation for this work is to construct a map from classical knots to virtual ones. What we get in the paper is a series of maps from knots in the full torus (thickened torus) to flat-virtual knots. We give definition of flat-virtual…

Geometric Topology · Mathematics 2024-06-21 V. O. Manturov , I. M. Nikonov

This paper describes a polynomial invariant of virtual knots that is defined in terms of an integer labeling of the virtual knot diagram. This labeling is seen to derive from an essentially unique structure of affine flat biquandle for flat…

Algebraic Topology · Mathematics 2014-07-25 Louis H. Kauffman

In this paper we introduce the notion of an unknotting index for virtual knots. We give some examples of computation by using writhe invariants, and discuss a relationship between the unknotting index and the virtual knot module. In…

Geometric Topology · Mathematics 2017-09-05 K. Kaur , S. Kamada , A. Kawauchi , M. Prabhakar

This paper studies cobordism and concordance for virtual knots. We define the affine index polynomial, prove that it is a concordance invariant for knots and links (explaining when it is defined for links), show that it is also invariant…

Geometric Topology · Mathematics 2018-07-26 Louis H Kauffman

F-polynomials for virtual knots were defined by Kaur, Prabhakar and Vesnin in 2018 using flat virtual knot invariants. These polynomials naturally generalize Kauffman's affine index polynomial and use smoothing in classical crossing of a…

Geometric Topology · Mathematics 2021-11-09 Amrendra Gill , Maxim Ivanov , Madeti Prabhakar , Andrei Vesnin

We prove that parities on virtual knots come from invariant 1-cycles on the arcs of knot diagrams. In turn, the invariant cycles are determined by quasi-indices on the crossings of the diagrams. The found connection between the parities and…

Geometric Topology · Mathematics 2021-10-19 Igor Nikonov

We define an invariant of welded virtual knots from each finite crossed module by considering crossed module invariants of ribbon knotted surfaces which are naturally associated with them. We elucidate that the invariants obtained are non…

Geometric Topology · Mathematics 2017-05-23 Louis H. Kauffman , João Faria Martins

In the present paper, we address the problem how to get a map from knots in the cylinder and on the thickened torus to some (generalisation of) virtual knots called virtual-flat knots. The main construction takes a diagram on a cylinder…

Geometric Topology · Mathematics 2022-10-19 V. O. Manturov , I. M. Nikonov

In this note, we construct a chord index homomorphism from a subgroup of $H_1(\Sigma, \mathbb{Z})$ to the group of chord indices of a knot $K$ in $\Sigma\times I$. Some knot invariants derived from this homomorphism are discussed.

Geometric Topology · Mathematics 2025-09-03 Zhiyun Cheng , Hongzhu Gao , Mengjian Xu

We construct various functorial maps (projections) from virtual knots to classical knots. These maps are defined on diagrams of virtual knots; in terms of Gauss diagram each of them can be represented as a deletion of some chords. The…

Geometric Topology · Mathematics 2012-09-04 Vassily Olegovich Manturov

In this paper, we define some polynomial invariants for virtual knots and links. In the first part we use Manturov's parity axioms to obtain a new polynomial invariant of virtual knots. This invariant can be regarded as a generalization of…

Geometric Topology · Mathematics 2013-12-31 Zhiyun Cheng , Hongzhu Gao

In 2002, D. Hrencecin and L.H. Kauffman defined a filamentation invariant on oriented chord diagrams that may determine whether the corresponding flat virtual knot diagrams are non-trivial. A virtual knot diagram is non-classical if its…

Geometric Topology · Mathematics 2007-05-23 William J. Schellhorn

In this paper, we discuss filamentations on oriented chord diagrams. When a filamentation cannot be realized on an oriented chord diagram, then the corresponding flat virtual knot is non-trivial. If a flat knot diagram is non-trivial, then…

Geometric Topology · Mathematics 2007-05-23 David Hrencecin , Louis H. Kauffman

The notion of a braided chord diagram is introduced and studied. An equivalence relation is given which identifies all braidings of a fixed chord diagram. It is shown that finite-type invariants are stratified by braid index for knots which…

Geometric Topology · Mathematics 2007-05-23 Joan S. Birman , Rolland Trapp

Virtual index cocycle is the 1-cochain that counts virtual crossings in the arcs of a virtual link diagram. We show how this cocycle can be used to reformulate and unify some known invariants of virtual links.

Geometric Topology · Mathematics 2020-11-03 Igor Nikonov

We introduce a new combinatorial method to encode knots and links with applications to knot invariants. Clasp diagrams defined in this paper are combinatorial blueprints for building knot diagrams out of full twists on two strings rather…

Geometric Topology · Mathematics 2019-11-11 Jacob Mostovoy , Michael Polyak

We construct an invariant of virtual knots which is a sliceness obstruction and sensitive to the $\Delta$-move. This invariants works if $\Z_{2}\oplus \Z_{2}$-index of chords is present.

Geometric Topology · Mathematics 2022-01-04 Vassily Olegovich Manturov

Piecewise-linear virtual knots are discussed and classified up to edge index six.

Geometric Topology · Mathematics 2009-07-14 Neil R. Nicholson
‹ Prev 1 2 3 10 Next ›