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In this paper we use continued fractions to study a partial order on the set of 2-bridge knots derived from the work of Ohtsuki, Riley, and Sakuma. We establish necessary and sufficient conditions for any set of 2-bridge knots to have an…

Geometric Topology · Mathematics 2011-01-24 Scott M. Garrabrant , Jim Hoste , Patrick D. Shanahan

The theory of tunnel number 1 knots detailed in our previous paper, The tree of knot tunnels, provides a non-negative integer invariant called the depth of the tunnel. We give various results related to the depth invariant. Noting that it…

Geometric Topology · Mathematics 2007-08-28 Sangbum Cho , Darryl McCullough

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 lattice stick number of knots is defined to be the minimal number of straight sticks in the cubic lattice required to construct a lattice stick presentation of the knot. We similarly define the lattice stick number $s_{L}(G)$ of spatial…

Geometric Topology · Mathematics 2018-06-27 Hyungkee Yoo , Chaeryn Lee , Seungsang Oh

An $n$-crossing projection of a link $L$ is a projection of $L$ onto a plane such that $n$ points on $L$ are superimposed on top of each other at every crossing. We prove that for all $k \in \mathbb{N}$ and all links $L$, the inequality…

Geometric Topology · Mathematics 2020-10-30 Anshul Guha

The braid indices of most links remain unknown as there is no known universal method that can be used to determine the braid index of an arbitrary knot. This is also the case for alternating knots. In this paper, we show that if $K$ is an…

Geometric Topology · Mathematics 2024-08-28 Yuanan Diao , Hugh Morton

A petal projection of a knot $K$ is a projection of a knot which consists of a single multi-crossing and non-nested loops. Since a petal projection gives a sequence of natural numbers for a given knot, the petal projection is a useful model…

Geometric Topology · Mathematics 2022-09-30 Hyoungjun Kim , Sungjong No , Hyungkee Yoo

In this paper, we show the trivializing number of all minimal diagrams of positive 2-bridge knots and study the relation between the trivializing number and the unknotting number for a part of these knots.

Geometric Topology · Mathematics 2016-02-24 Kazuhiko Inoue

The splitting number of a link is the minimal number of crossing changes between different components required to convert it into a split link. We obtain a lower bound on the splitting number in terms of the (multivariable) signature and…

Geometric Topology · Mathematics 2016-10-27 David Cimasoni , Anthony Conway , Kleopatra Zacharova

Extending upon our previous work, we verify the Jones Unknot Conjecture for all knots up to $24$ crossings. We describe the method of our approach and analyze the growth of the computational complexity of its different components.

Geometric Topology · Mathematics 2021-03-25 Robert E. Tuzun , Adam S. Sikora

In Dunfield's catalog of the hyperbolic manifolds in the SnapPy census which are complements of L-space knots in $S^3$, we determine that $22$ have tunnel number $2$ while the remaining all have tunnel number $1$. Notably, these $22$…

We introduce a new way to tabulate knots by representing knot diagrams using a pair of planar trees. This pair of trees have their edges labeled by integers, they have no valence 2 vertices, and they have the same number of valence 1…

Geometric Topology · Mathematics 2007-05-23 Lisa Hernandez , Xiao-Song Lin

We prove that if an alternating 3-braid knot has unknotting number one, then there must exist an unknotting crossing in any alternating diagram of it, and we enumerate such knots. The argument combines the obstruction to unknotting number…

Geometric Topology · Mathematics 2009-02-11 Joshua Greene

In a recent paper, the first author and his collaborator developed a method to compute an upper bound of the dimension of instanton Floer homology via Heegaard Diagrams of 3-manifolds. For a knot inside S3, we further develop an algorithm…

Geometric Topology · Mathematics 2023-02-24 Zhenkun Li , Yi Liang

For a knot $K$, the doubly slice genus $g_{ds}(K)$ is the minimal $g$ such that $K$ divides a closed, orientable, and unknotted surface of genus $g$ embedded in $S^4$. In this paper, we identify the doubly slice genera of 2909 of the 2977…

Geometric Topology · Mathematics 2021-09-13 Lucia P. Karageorghis , Frank Swenton

Given a diagram $D$ of a knot $K$, we consider the number $c(D)$ of crossings and the number $b(D)$ of overpasses of $D$. We show that, if $D$ is a diagram of a nontrivial knot $K$ whose number $c(D)$ of crossings is minimal, then…

Geometric Topology · Mathematics 2009-11-10 Jae-Wook Chung , Xiao-Song Lin

We define and compare several natural ways to compute the bridge number of a knot diagram. We study bridge numbers of crossing number minimizing diagrams, as well as the behavior of diagrammatic bridge numbers under the connected sum…

Geometric Topology · Mathematics 2021-07-09 Ryan Blair , Alexandra A. Kjuchukova , Makoto Ozawa

Flat plumbing basket surfaces of links were introduced to study the geometry of the complement of the links. These flat plumbing basket surface can be presented by a sequential presentation known as flat plumbing basket code first found by…

Geometric Topology · Mathematics 2015-07-06 Yoon-Ho Choi , Yun Ki Chung , Dongseok Kim

The knot Floer order $\operatorname{Ord}(K)$ is a knot invariant derived from knot Floer homology that provides bounds on many other invariants, such as the bridge index $\operatorname{br}(K)$ for which $\operatorname{Ord}(K) + 1 \leq…

Geometric Topology · Mathematics 2025-09-26 David Suchodoll

We give examples of knots with some unusual properties of the crossing number of positive diagrams or strand number of positive braid representations. In particular we show that positive braid knots may not have positive minimal (strand…

Geometric Topology · Mathematics 2007-05-23 A. Stoimenow