Hard Diagrams of the Unknot

Publication date

2024-07

Authors

Burton, Benjamin A.
Chang, Hsien Chih
Löffler, MaartenISNI 000000039666142X
Maria, Clément
de Mesmay, Arnaud
Schleimer, Saul
Sedgwick, Eric
Spreer, Jonathan

Editors

Advisors

Supervisors

Document Type

Article
Open Access logo

License

taverne

Abstract

We present three “hard” diagrams of the unknot. They require (at least) three extra crossings before they can be simplified to the trivial unknot diagram via Reidemeister moves in (Formula presented.). Two of them are constructed by applying previously proposed methods. The proof of their hardness uses significant computational resources. We also determine that no small “standard” example of a hard unknot diagram requires more than one extra crossing for Reidemeister moves in (Formula presented.).

Keywords

Knot theory, mathematical software, Reidemeister moves, unknot, unknot recognition problem, Taverne, General Mathematics

Citation

Burton, B A, Chang, H C, Löffler, M, Maria, C, de Mesmay, A, Schleimer, S, Sedgwick, E & Spreer, J 2024, 'Hard Diagrams of the Unknot', Experimental Mathematics, vol. 33, no. 3, pp. 482-500. https://doi.org/10.1080/10586458.2022.2161676