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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

We introduce an unknotting-type number of knot projections that gives an upper bound of the crosscap number of knots. We determine the set of knot projections with the unknotting-type number at most two, and this result implies classical…

Geometric Topology · Mathematics 2020-08-26 Noboru Ito , Yusuke Takimura

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 observe that any knot invariant extends to virtual knots. The isotopy classification problem for virtual knots is reduced to an algebraic problem formulated in terms of an algebra of arrow diagrams. We introduce a new notion of finite…

Geometric Topology · Mathematics 2007-05-23 M. Goussarov , M. Polyak , O. Viro

This paper gives an alternate definition of the Affine Index Polynomial (called the Wriggle Polynomial) using virtual linking numbers and explores applications of this polynomial. In particular, it proves the Cosmetic Crossing Change…

Geometric Topology · Mathematics 2012-11-09 Lena C. Folwaczny , Louis H. Kauffman

We introduce several new concepts about graphs and investigate their basic properties. A longest path in a graph is called a detour and a longest cycle is called a cummerbund. The detour covering number of a graph is the number of vertices…

Combinatorics · Mathematics 2025-05-08 Chengli Li , Xingzhi Zhan

A realization of a virtual link diagram is obtained by choosing over/under markings for each virtual crossing. Any realization can also be obtained from some representation of the virtual link. (A representation of a virtual link is a link…

Geometric Topology · Mathematics 2007-05-23 H. A. Dye

We introduce the warping polynomial of an oriented knot diagram. In this paper, we characterize the warping polynomial, and define the span of a knot to be the minimal span of the warping polynomial for all diagrams of the knot. We show…

Geometric Topology · Mathematics 2011-12-12 Ayaka Shimizu

We study groups of some virtual knots with small number of crossings and prove that there is a virtual knot with long lower central series which, in particular, implies that there is a virtual knot with residually nilpotent group. This…

Geometric Topology · Mathematics 2020-07-21 Valeriy G. Bardakov , Neha Nanda , Mikhail V. Neshchadim

Both classical and virtual knots arise as formal Gauss diagrams modulo some abstract moves corresponding to Reidemeister moves. If we forget about both over/under crossings structure and writhe numbers of knots modulo the same Reidemeister…

Geometric Topology · Mathematics 2009-02-03 Vassily Olegovich Manturov

This paper is a concise introduction to virtual knot theory, coupled with a list of research problems in this field.

Geometric Topology · Mathematics 2014-09-10 Roger Fenn , Denis P. Ilyutko , Louis H. Kauffman , Vassily O. Manturov

Classical knots in $\mathbb{R}^3$ can be represented by diagrams in the plane. These diagrams are formed by curves with a finite number of transverse crossings, where each crossing is decorated to indicate which strand of the knot passes…

Geometric Topology · Mathematics 2013-09-30 Allison Henrich , Rebecca Hoberg , Slavik Jablan , Lee Johnson , Elizabeth Minten , Ljiljana Radovic

We have developed a reinforcement learning agent that often finds a minimal sequence of unknotting crossing changes for a knot diagram with up to 200 crossings, hence giving an upper bound on the unknotting number. We have used this to…

The algebraic unknotting number u_a(K) of a knot K was introduced by Hitoshi Murakami. It equals the minimal number of crossing changes needed to turn K into an Alexander polynomial one knot. In a previous paper the authors used the…

Geometric Topology · Mathematics 2013-08-29 Maciej Borodzik , Stefan Friedl

The slicing degree of a knot $K$ is defined as the smallest integer $k$ such that $K$ is $k$-slice in $\#^n \overline{\mathbb{CP}^2}$ for some $n$. In this paper, we establish bounds for the slicing degrees of knots using Rasmussen's…

Geometric Topology · Mathematics 2024-04-25 Qianhe Qin

An $n$-crossing is a point in the projection of a knot where $n$ strands cross so that each strand bisects the crossing. An \"ubercrossing projection has a single $n$-crossing and a petal projection has a single $n$-crossing such that there…

Any knot diagram can be transformed into the unknot by a series of unknotting operations. This paper introduces the diagonal move, a novel unknotting operation that generalizes and unifies several existing moves. We prove that the diagonal…

Geometric Topology · Mathematics 2026-03-19 Danish Ali , Zhiqing Yang , Mohd Ibrahim Sheikh , Sidra Batool

We use the Chebyshev knot diagram model of Koseleff and Pecker in order to introduce a random knot diagram model by assigning the crossings to be positive or negative uniformly at random. We give a formula for the probability of choosing a…

Geometric Topology · Mathematics 2015-08-14 Moshe Cohen , Sunder Ram Krishnan

This paper is expository and is accessible to students. We define simple invariants of knots or links (linking number, Arf-Casson invariants and Alexander-Conway polynomials) motivated by interesting results whose statements are accessible…

Geometric Topology · Mathematics 2021-12-15 A. Skopenkov

We establish a Kauffman-Murasugi-Thistlethwaite-type theorem for alternating knots in a solid torus. Specifically, we show that any dotted-reduced alternating diagram of a knot in a handlebody realizes the minimal crossing number, and that…

Geometric Topology · Mathematics 2026-01-30 Lizzie Buchanan , Tanushree Shah