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The crossing number of a graph $G$ is the minimum number of pairwise intersections of edges among all drawings of $G$. In this paper, we study the crossing number of $K_{n,n}-nK_2$, $K_n\times P_2$, $K_n\times P_3$ and $K_n\times C_4$.

Discrete Mathematics · Computer Science 2012-11-20 Yuansheng Yang , Baigong Zheng , Xiaohui Lin , Xirong Xu

In this paper, we enumerate the number of oriented rational knots and the number of oriented rational links with any given crossing number and minimum genus. This allows us to obtain a precise formula for the average minimal genus of…

Geometric Topology · Mathematics 2022-04-28 Dawn Ray , Yuanan Diao

Symmetries of knots have been studied extensively, and strongly invertible knots are one of them. Lamm defined the equivariant crossing number $c_t(K)$, the minimum crossing number among all symmetric diagrams for a strongly invertible knot…

Geometric Topology · Mathematics 2023-04-04 Jundai Nanasawa

For a knot K, the concordance crosscap number, c(K), is the minimum crosscap number among all knots concordant to K. Building on work of G. Zhang, which studied the determinants of knots with c(K) < 2, we apply the Alexander polynomial to…

Geometric Topology · Mathematics 2013-10-29 Charles Livingston

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

In this article we take up the calculation of the minimum number of colors needed to produce a non-trivial coloring of a knot. This is a knot invariant and we use the torus knots of type (2, n) as our case study. We calculate the minima in…

Geometric Topology · Mathematics 2011-11-10 Louis H. Kauffman , Pedro Lopes

The stick number of a knot is the minimum number of segments needed to build a polygonal version of the knot. Despite its elementary definition and relevance to physical knots, the stick number is poorly understood: for most knots we only…

Geometric Topology · Mathematics 2023-01-09 Thomas D. Eddy , Clayton Shonkwiler

The simultaneous crossing number is a new knot invariant which is defined for strongly invertible knots having diagrams with two orthogonal transvergent axes of strong inversions. Because the composition of the two inversions gives a cyclic…

Geometric Topology · Mathematics 2025-04-16 Christoph Lamm , Michael Eisermann

We introduce a new numerical knot invariant, termed the \textit{segment number}, which is derived from partitioned knot diagrams subject to specific over/under-crossing constraints. We prove that a knot is non-trivial if and only if its…

Geometric Topology · Mathematics 2026-02-19 Makoto Ozawa

The warping degree of an oriented knot diagram is the minimal number of crossings which we meet as an under-crossing first when we travel along the diagram from a fixed point. The warping degree of a knot projection is the minimal value of…

Geometric Topology · Mathematics 2021-01-25 Atsushi Ohya , Ayaka Shimizu

If a knot has the Alexander polynomial not equal to 1, then it is linear $n$-colorable. By means of such a coloring, such a knot is given an upper bound for the minimal quandle order, i.e., the minimal order of a quandle with which the knot…

Geometric Topology · Mathematics 2012-02-29 Chuichiro Hayashi , Miwa Hayashi , Kanako Oshiro

We define the concordance crosscap number of a knot as the minimum crosscap number among all the knots concordant to the knot. The four-dimensional crosscap number is the minimum first Betti number of non-orientable surfaces smoothly…

Geometric Topology · Mathematics 2007-05-23 Gengyu Zhang

A long standing open conjecture states that if a link $\mathcal{K}$ is alternating, then its ropelength $L(\mathcal{K})$ is at least of the order $O(Cr(\mathcal{K}))$. A recent result shows that the maximum braid index of a link bounds the…

Geometric Topology · Mathematics 2021-08-25 Yuanan Diao

A quadruple crossing is a crossing in a projection of a knot or link that has four strands of the knot passing straight through it. A quadruple crossing projection is a projection such that all of the crossings are quadruple crossings. In a…

Geometric Topology · Mathematics 2019-02-20 Colin Adams

The crossing number of a graph is the minimum number of crossings in a drawing of the graph in the plane. Our main result is that every graph $G$ that does not contain a fixed graph as a minor has crossing number $O(\Delta n)$, where $G$…

Combinatorics · Mathematics 2018-08-01 Vida Dujmović , Ken-ichi Kawarabayashi , Bojan Mohar , David R. Wood

We use a version of simulated annealing with knot-type preserving moves to find polygonal representatives of various knot types with low stick number. These give better bounds on stick numbers of prime knots through 10 crossings, and for…

Geometric Topology · Mathematics 2025-08-26 Jason Cantarella , Andrew Rechnitzer , Henrik Schumacher , Clayton Shonkwiler

In this work we establish the tightest lower bound up-to-date for the minimal crossing number of a satellite knot based on the minimal crossing number of the companion used to build the satellite. If $M$ is the wrapping number of the…

Geometric Topology · Mathematics 2017-12-18 Adrián Jiménez Pascual

For any link in the 3-sphere, there is a natural lower bound for the unlinking number in terms of the classical signature. We prove that if this lower bound is sharp for a special alternating link $L$, then the unlinking number of $L$ is…

Geometric Topology · Mathematics 2026-03-25 Duncan McCoy , JungHwan Park

This paper bounds the computational cost of computing the Kauffman bracket of a link in terms of the crossing number of that link. Specifically, it is shown that the image of a tangle with $g$ boundary points and $n$ crossings in the…

Geometric Topology · Mathematics 2013-03-29 Lauren Ellenberg , Gabriella Newman , Stephen Sawin , Jonathan Shi

Given a knot $K$ parametrized by $r: [0,2\pi] \to \mathbb{R}^3$, we can define the electric potential on its complement by $\Phi(x) = \int_0^{2\pi} \frac{|r'(t)|}{|x - r(t)|}dt$. Physicists and knot theorists want to understand the critical…

Dynamical Systems · Mathematics 2021-04-02 Max Lipton