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We are giving tables of quasi-alternating knots with $8\le n \le 12$ crossings. As the obstructions for a knot to be quasialternating we used homology thickness with regards to Khovanov homology, odd homology, and Heegaard-Floer homology…

Geometric Topology · Mathematics 2014-04-23 Slavik Jablan

The unknotting number of a knot is bounded from below by its slice genus. It is a well-known fact that the genera and unknotting numbers of torus knots coincide. In this note we characterize quasipositive knots for which the genus bound is…

Geometric Topology · Mathematics 2015-05-13 Sebastian Baader

We prove that any $11$-colorable knot is presented by an $11$-colored diagram where exactly five colors of eleven are assigned to the arcs. The number five is the minimum for all non-trivially $11$-colored diagrams of the knot. We also…

Geometric Topology · Mathematics 2015-05-13 Takuji Nakamura , Yasutaka Nakanishi , Shin Satoh

A (weak chord) index is a function on the crossings of knot diagrams such that: 1) the index of a crossing does not change under Reidemeister moves; 2) crossings which can be paired by a second Reidemeister move have the same index. We show…

Geometric Topology · Mathematics 2022-02-23 Igor Nikonov

Introduced recently, an n-crossing is a singular point in a projection of a link at which n strands cross such that each strand travels straight through the crossing. We introduce the notion of an \"ubercrossing projection, a knot…

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

A $k$-crossing family in a point set $S$ in general position is a set of $k$ segments spanned by points of $S$ such that all $k$ segments mutually cross. In this short note we present two statements on crossing families which are based on…

Computational Geometry · Computer Science 2022-10-03 Oswin Aichholzer , Jan Kynčl , Manfred Scheucher , Birgit Vogtenhuber , Pavel Valtr

Suppose that every non-minimal bridge position of a knot $K$ is perturbed. We show that if $L$ is a $(2, 2q)$-cable link of $K$, then every non-minimal bridge position of $L$ is also perturbed.

Geometric Topology · Mathematics 2020-09-11 Jung Hoon Lee

In a lens space X of order r a knot K representing an element of the fundamental group pi_1 X = Z/rZ of order s <= r contains a connected orientable surface S properly embedded in its exterior X-N(K) such that the boundary of S intersects…

Geometric Topology · Mathematics 2009-04-30 Kenneth L Baker

The exact crossing number is only known for a small number of families of graphs. Many of the families for which crossing numbers have been determined correspond to cartesian products of two graphs. Here, the cartesian product of the Sunlet…

Combinatorics · Mathematics 2019-02-28 Michael Haythorpe , Alex Newcombe

We determine the rational Khovanov bigraded homology groups of all Kanenobu knots. Also, we determine the crossing number for all Kanenobu knots $K(p,q)$ with $pq > 0$ or $|pq|\leq \max \{|p|, |q|\}$. In the case where $pq < 0$ and $|pq| >…

Geometric Topology · Mathematics 2014-05-06 Khaled Qazaqzeh , Isra Mansour

A knot K is called n-adjacent to the unknot, if K admits a projection containing n generalized crossings such that changing any m (no larger than n) of them yields a projection of the unknot. We show that a non-trivial satellite knot K is…

Geometric Topology · Mathematics 2007-05-23 Efstratia Kalfagianni , Xiao-Song Lin

We give a locally minimal, but not globally minimal bridge position of a knot, that is, an unstabilized, nonminimal bridge position of a knot. It implies that a bridge position cannot always be simplified so that the bridge number…

Geometric Topology · Mathematics 2013-06-05 Makoto Ozawa , Kazuto Takao

Given a knot $K$ in a closed orientable manifold $M$ we define the growth rate of the tunnel number of $K$ to be $gr_t(K) = \limsup_{n \to \infty} \frac{t(nK) - n t(K)}{n-1}$. As our main result we prove that the Heegaard genus of $M$ is…

Geometric Topology · Mathematics 2007-05-23 Tsuyoshi Kobayashi , Yo'av Rieck

We show that a finite numerical boundary slope of an essential surface in the exterior of a Montesinos knot is bounded above and below in terms of the numbers of positive/negative crossings of a specific minimal diagram of the knot.

Geometric Topology · Mathematics 2008-09-26 Kazuhiro Ichihara , Shigeru Mizushima

We show that the crossing number of any link that is known to be quasi-alternating is less than or equal to its determinant. Based on this, we conjecture that the crossing number of any quasi-alternating link is less than or equal to its…

Geometric Topology · Mathematics 2012-05-22 Khaled Qazaqzeh , Balkees Qublan , Abeer Jaradat

A conjecture proposed by J. Tripp in 2002 states that the crossing number of any knot coincides with the canonical genus of its Whitehead double. In the meantime, it has been established that this conjecture is true for a large class of…

Geometric Topology · Mathematics 2015-10-06 Hee Jeong Jang , Sang Youl Lee

Since the crossing number of K_{12} is now known to be 150, it is well-known that simple counting arguments and Kleitman's parity theorem for the crossing number of K_{2n+1} combine with a specific drawing of K_{13} to show that the…

Combinatorics · Mathematics 2013-07-15 Dan McQuillan , Shengjun Pan , R. Bruce Richter

For a positive integer $k$, a graph is $k$-knitted if for each $k$-subset $S$ of vertices, and every partition of $S$ into disjoint parts $S_1, \ldots, S_t$ for some $t\ge 1$, one can find disjoint connected subgraphs $C_1, \ldots, C_t$…

Combinatorics · Mathematics 2019-06-11 Runrun Liu , Martin Rolek , Gexin Yu

An \"{u}bercrossing diagram is a knot diagram with only one crossing that may involve more than two strands of the knot. Such a diagram without any nested loops is called a petal projection. Every knot has a petal projection from which the…

Geometric Topology · Mathematics 2022-08-10 Allison Henrich , Robin Truax