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We prove obstructions to a strongly negative amphichiral knot bounding an equivariant slice disk in the 4-ball using the determinant, Spinc-structures and Donaldson's theorem. Of the 16 slice strongly negative amphichiral knots with 12 or…

Geometric Topology · Mathematics 2024-04-24 Keegan Boyle , Ahmad Issa

We specify the computational complexity of crosscap numbers of alternating knots by introducing an automatic computation. For an alternating knot $K$, let $\cal{E}$ be the number of edges of its diagram. Then there exists a code such that…

Geometric Topology · Mathematics 2023-03-20 Kaito Yamada , Noboru Ito

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

We prove that a special alternating knot does not decompose as a non-trivial band sum. This restricts concordances from special alternating knots, and we conjecture that special alternating knots are ribbon concordance minimal. We verify…

Geometric Topology · Mathematics 2024-12-17 Joe Boninger , Joshua Evan Greene

A knot in the three-sphere is doubly slice if it is the cross-section of an unknotted two-sphere in the four-sphere. For low-crossing knots, the most complete work to date gives a classification of doubly slice knots through 9 crossings. We…

Geometric Topology · Mathematics 2016-10-19 Charles Livingston , Jeffrey Meier

We explore the application of automated reasoning techniques to unknot detection, a classical problem of computational topology. We adopt a two-pronged experimental approach, using a theorem prover to try to establish a positive result…

Logic in Computer Science · Computer Science 2014-05-19 Andrew Fish , Alexei Lisitsa

We resolve parts (A) and (B) of Problem 1.100 from Kirby's list by showing that many nontrivial links arise as cross-sections of unknotted holomorphic disks in the four-ball. The techniques can be used to produce unknotted ribbon surfaces…

Geometric Topology · Mathematics 2019-02-20 Kyle Hayden

Frequently, knots are enumerated by their crossing number. However, the number of knots with crossing number $c$ grows exponentially with $c$, and to date computer-assisted proofs can only classify diagrams up to around twenty crossings.…

Geometric Topology · Mathematics 2018-12-03 Yoav Moriah , Jessica S. Purcell

Algorithm of construction of all knots, links with given number of crosses on diagram of knot, link is offered. This algorithm is based on simple proposition, that there is a representation of knot (link) as closure of braid with n threads…

Geometric Topology · Mathematics 2007-05-23 S. S. Serova , S. A. Serov

For any given number of crossings $c$, there exists a formula to determine the number of 2-bridge knots of $c$ crossings, and indeed it is a simple matter to actually construct presentations of these knots. However, the determination of…

Geometric Topology · Mathematics 2007-05-23 David De Wit

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

We present an enhanced prime decomposition theorem for knots that gives the isotopy classes of composite knots that can be constructed from a given list of prime factors (allowing for the mirroring and orientation reversing for each…

Geometric Topology · Mathematics 2014-11-14 Matt Mastin

In a previous work, the first and third authors studied a random knot model for all two-bridge knots using billiard table diagrams. Here we present a closed formula for the distribution of the crossing numbers of such random knots. We also…

Geometric Topology · Mathematics 2018-08-13 Moshe Cohen , Chaim Even-Zohar , Sunder Ram Krishnan

The alternating knots, links and twists projected on the $S_2$ sphere were identified with the phase space of a Hamiltonian dynamic system of one degree of freedom. The saddles of the system correspond to the crossings, the edges correspond…

Geometric Topology · Mathematics 2007-12-14 E. Piña

Using exhaustive techniques and results from Lackenby and many others, we compute the tunnel number of all 1655 alternating 11 and 12 crossing knots and of 881 non-alternating 11 and 12 crossing knots. We also find all 5525 Montesinos knots…

Geometric Topology · Mathematics 2022-03-23 Felipe Castellano-Macías , Nicholas Owad

It is known that the arc index of alternating knots is the minimal crossing number plus two and the arc index of prime nonalternating knots is less than or equal to the minimal crossing number. We study some cases when the arc index is…

Geometric Topology · Mathematics 2011-06-15 Gyo Taek Jin , Hwa Jeong Lee

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

In this article, we give a list of minimal grid diagrams of the 12 crossing prime alternating knots. This is a continuation of the work in https://doi.org/10.1142/S0218216520500765

Geometric Topology · Mathematics 2020-12-29 Gyo Taek Jin , Hwa Jeong Lee

Let $M$ be a connected, closed, oriented three-manifold and $K$, $L$ two rationally null-homologous oriented simple closed curves in $M$. We give an explicit algorithm for computing the linking number between $K$ and $L$ in terms of a…

Geometric Topology · Mathematics 2021-07-09 Patricia Cahn , Alexandra Kjuchukova

This is the first in a series of four papers wherein we enumerate all prime alternating knots and links. In this first paper, we introduce four operators on knots and show that, when used according to very simple rules on the prime…

Geometric Topology · Mathematics 2007-05-23 Ortho Smith , John Schermann , Stuart Rankin