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We provide linear lower bounds for the signature of positive braids in terms of the three genus of their braid closure. This yields linear bounds for the topological slice genus of knots that arise as closures of positive braids.

Geometric Topology · Mathematics 2015-10-15 Peter Feller

We derive a linear estimate of the signature of positive knots, in terms of their genus. As an application, we show that every knot concordance class contains at most finitely many positive knots.

Geometric Topology · Mathematics 2018-05-16 Sebastian Baader , Pierre Dehornoy , Livio Liechti

For certain classes of knots we define geometric invariants called higher-order genera. Each of these invariants is a refinement of the slice genus of a knot. We find lower bounds for the higher-order genera in terms of certain von Neumann…

Geometric Topology · Mathematics 2010-06-03 Peter D. Horn

It has been conjectured that the geometric invariant of knots in 3-space called the width is nearly additive. That is, letting w(K) in N denote the width of a knot K in S^3, the conjecture is that w(K # K') = w(K) + w(K') - 2. We give an…

Geometric Topology · Mathematics 2007-05-23 Martin Scharlemann , Abigail Thompson

Let $u(K)$ and $g(K)$ denote the unknotting number and the genus of a knot $K$, respectively. For a 3-braid knot $K$, we show that $u(K)\le g(K)$ holds, and that if $u(K)=g(K)$ then $K$ is either a 2-braid knot, a connected sum of two…

Geometric Topology · Mathematics 2014-01-28 Eon-Kyung Lee , Sang-Jin Lee

The unknotting number of a positive braid with n strands and k intersections is known to be equal to (k-n+1)/2. We consider Lorenz knots (which are positive braids) and, using a different method, find their unknotting numbers in terms of…

Geometric Topology · Mathematics 2015-03-04 Lilya Lyubich

The Turaev genus of a knot is a topological measure of how far a given knot is from being alternating. Recent work by several authors has focused attention on this interesting invariant. We discuss how the Turaev genus is related to other…

Geometric Topology · Mathematics 2016-08-02 Abhijit Champanerkar , Ilya Kofman

Given a knot in $S^3$, one can associate to it a surface diffeomorphism in two different ways. First, an arbitrary knot in $S^{3}$ can be represented by braids, which can be thought of as diffeomorphisms of punctured disks. Second, if the…

We extend the classical definition of {\it width} to higher dimensional, smooth codimension 2 knots and show in each dimension there are knots of arbitrarily large width.

Geometric Topology · Mathematics 2021-02-24 Michael Freedman , Jonathan Hillman

For a knot K, let b_n(K) be the minimum length of an n-stranded braid representative of K. Examples of knots exist for which b_n(K) is a non-increasing function. We investigate the behavior of b_n(K). We develop bounds on the function in…

Geometric Topology · Mathematics 2014-10-01 Cornelia A. Van Cott

If a knot K in a closed, orientable 3-manifold M has a bridge surface T with distance at least 3 in the curve complex of T - K, then the genus of any essential surface in its exterior with non-empty, non-meridional boundary gives rise to an…

Geometric Topology · Mathematics 2012-11-21 Ryan Blair , Marion Campisi , Jesse Johnson , Scott A. Taylor , Maggy Tomova

We define the height of a mixed motive over a number field extending our previous work for pure motives.

Number Theory · Mathematics 2013-07-04 Kazuya Kato

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

This paper investigates the relationship between the signature and the crossing number of knots and links. We refine existing theorems and provide a comprehensive classification of links with specific properties, particularly those with…

Geometric Topology · Mathematics 2024-10-02 Kai Ishihara , Kei Okada , Koya Shimokawa

We study the properties of glued knots, a sub-class of real rational knots, that can be constructed by gluing ellipses. We define an invariant called the gluing degree and relate it to various classical properties of knots and classify all…

Geometric Topology · Mathematics 2021-07-28 Shane D'Mello , Vinay Gaba

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

Let $k$ be a finite field extension of the function field $\bfF_p(T)$ and $\bar{k}$ its algebraic closure. We count points in projective space $\Bbb P ^{n-1}(\bar{k})$ with given height and of fixed degree $d$ over the field $k$. If…

Number Theory · Mathematics 2014-02-26 Jeffrey Lin Thunder , Martin Widmer

We prove that a knot is the unknot if and only if its reduced Khovanov cohomology has rank 1. The proof has two steps. We show first that there is a spectral sequence beginning with the reduced Khovanov cohomology and abutting to a knot…

Geometric Topology · Mathematics 2010-05-25 P. B. Kronheimer , T. S. Mrowka

We discuss the polynomial representation for long knots and elaborate on how to obtain them with a bound on degrees of the defining polynomials, for any knot-type.

Geometric Topology · Mathematics 2008-03-24 Rama Mishra , M. Prabhakar

The second author proved that the set of post-critically finite polynomials of given degree is a set of bounded height, up to change of variables. Motivated by an observation about unicritical polynomials, we complement this by proving that…

Number Theory · Mathematics 2022-10-27 Benjamin Fraser , Patrick Ingram