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We define a new topological invariant of line arrangements in the complex projective plane. This invariant is a root of unity defined under some combinatorial restrictions for arrangements endowed with some special torsion character on the…

Geometric Topology · Mathematics 2018-05-04 Enrique Artal Bartolo , Vincent Florens , Benoît Guerville-BallÉ

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

We introduce twelve polynomial invariants for long virtual knots, called intersection polynomials, extending and refining the three intersection polynomials for virtual knots. They are defined via intersection numbers of cycles on a closed…

Geometric Topology · Mathematics 2025-12-08 Takuji Nakamura , Yasutaka Nakanishi , Shin Satoh , Kodai Wada

Traditionally, knot theorists have considered projections of knots where there are two strands meeting at every crossing. A triple crossing is a crossing where three strands meet at a single point, such that each strand bisects the…

Geometric Topology · Mathematics 2018-05-14 Daishiro Nishida

Consider a continuous flow in $\mathbb{R}^3$ or any orientable $3$-manifold. Let $(Q_1, Q_0)$ be an index pair in the sense of Conley and consider the region $N := \overline{Q_1 - Q_0}$. (An example of this is a compact $3$-manifold $N$…

Dynamical Systems · Mathematics 2024-03-28 J. J. Sánchez-Gabites

Symmetry of geometrical figures is reflected in regularities of their algebraic invariants. Algebraic regularities are often preserved when the geometrical figure is topologically deformed. The most natural, intuitively simple but…

Geometric Topology · Mathematics 2007-05-23 Jozef H. Przytycki

We compose the table of knots in the thickened torus T x I having diagrams with at most 4 crossings. The knots are constructed by the three-step process. First we list regular graphs of degree 4 with at most 4 vertices, then for each graph…

Geometric Topology · Mathematics 2012-07-02 A. A. Akimova , S. V. Matveev

We describe an efficient algorithm to compute finite type invariants of type $k$ by first creating, for a given knot $K$ with $n$ crossings, a look-up table for all subdiagrams of $K$ of size $\lceil \frac{k}{2}\rceil$ indexed by dyadic…

Geometric Topology · Mathematics 2025-07-30 Dror Bar-Natan , Itai Bar-Natan , Iva Halacheva , Nancy Scherich

We introduce the notion of slice depth of a 2-knot K, which is the minimal integer n such that K is n-slice. We give an upper bound for the slice depth of the n-twist spin of a classical knot which belongs to several specific classes,…

Geometric Topology · Mathematics 2025-09-24 Ayaka Ise

A {\it stuck knot} is a knot diagram containing designated crossings, called {\it stuck crossings}, whose incident strands are required to remain locally non-separable. These rigidity constraints restrict the allowable ambient isotopies and…

Geometric Topology · Mathematics 2026-02-23 Ioannis Diamantis

We introduce three kinds of invariants of a virtual knot called the first, second, and third intersection polynomials. The definition is based on the intersection number of a pair of curves on a closed surface. The calculations of…

Geometric Topology · Mathematics 2022-01-26 Ryuji Higa , Takuji Nakamura , Yasutaka Nakanishi , Shin Satoh

In this paper we study embeddings of oriented connected closed surfaces in $\mathbb S^3$. We define a complete invariant, the fundamental span, for such embeddings, generalizing the notion of the peripheral system of a knot group. From the…

Geometric Topology · Mathematics 2021-05-25 Giovanni Bellettini , Maurizio Paolini , Yi-Sheng Wang

For a genus-1 1-bridge knot in the 3-sphere, that is, a (1,1)-knot, a middle tunnel is a tunnel that is not an upper or lower tunnel for some (1,1)-position. Most torus knots have a middle tunnel, and non-torus-knot examples were obtained…

Geometric Topology · Mathematics 2011-10-18 Sangbum Cho , Darryl McCullough

It has been conjectured that the algebraic crossing number of a link is uniquely determined in minimal braid representation. This conjecture is true for many classes of knots and links. The Morton-Franks-Williams inequality gives a lower…

Geometric Topology · Mathematics 2009-07-07 Keiko Kawamuro

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 demonstrate that three maximal subgroups of infinite index in the rectangular subgroup \( K_{(2,2)} \) of the Thompson group \( F \), each containing Jones's \( 3 \)-colorable subgroup \( \mathcal{F} \), can be characterized as…

Geometric Topology · Mathematics 2026-05-05 Valeriano Aiello

Every classical or virtual knot is equivalent to the unknot via a sequence of extended Reidemeister moves and the so-called forbidden moves. The minimum number of forbidden moves necessary to unknot a given knot is an invariant we call the…

Geometric Topology · Mathematics 2018-08-14 Alissa Crans , Sandy Ganzell , Blake Mellor

In view of the self-linking invariant, the number $|K|$ of framed knots in $S^3$ with given underlying knot $K$ is infinite. In fact, the second author previously defined affine self-linking invariants and used them to show that $|K|$ is…

Geometric Topology · Mathematics 2014-04-24 Patricia Cahn , Vladimir Chernov , Rustam Sadykov

A triple crossing is a crossing in a projection of a knot or link that has three strands of the knot passing straight through it. A triple crossing projection is a projection such that all of the crossings are triple crossings. We prove…

Geometric Topology · Mathematics 2012-09-05 Colin Adams

The Slope Conjecture relates a quantum knot invariant, (the degree of the colored Jones polynomial of a knot) with a classical one (boundary slopes of incompressible surfaces in the knot complement). The degree of the colored Jones…

Geometric Topology · Mathematics 2016-08-03 Stavros Garoufalidis , Roland van der Veen