Computation of Gordian distances and H2-Gordian distances of knots

Authors

  • Ana Zeković Faculty of Mathematics, Belgrade

DOI:

https://doi.org/10.2298/YJOR131210044Z

Keywords:

Unknotting number, Gordian distances, Smoothing distances, Weighted graph search

Abstract

One of the most complicated problems in Knot theory is to compute unknotting number. Hass, Lagarias and Pippenger proved that the unknotting problem is NP hard. In this paper we discuss the question of computing unknotting number from minimal knot diagrams, Bernhard-Jablan Conjecture, unknown knot distances between non-rational knots, and searching for minimal distances by using a graph with weighted edges, which represents knot distances. Since topoizomerazes are enzymes involved in changing crossing of DNA, knot distances can be used to study topoizomerazes actions. In the existing tables of knot smoothing, knots with smoothing number 1 are computed by Abe and Kanenobu [27] for knots with at most n = 9 crossings, and smoothing knot distances are computed by Kanenobu [26] for knots with at most n = 7 crossings. We compute some undecided knot distances 1 from these papers, and extend the computations by computing knots with smoothing number one with at most n = 11 crossings and smoothing knot distances of knots with at most n = 9 crossings. All computations are done in LinKnot, based on Conway notation and non-minimal representations of knots.

References

Nakanishi, Y., A note on unknotting number, Math. Sem. Notes Kobe Univ., 9 (1981) 99-108.

Kawauchi, A., A Survey of Knot Theory, Birkhuser, Basel, 1996.

Adams, C.C., The Knot Book, Freeman, New York, 1994.

Nakanishi, Y., Unknotting numbers and knot diagrams with the minimum crossings, Math. Sem. Notes Kobe Univ., 11 (1983) 257-258.

Bleiler, S.A., A note on unknotting number, Math. Proc. Camb. Phil. Soc., 96 (1984) 469-471.

Bernhard, J.A., Unknotting numbers and their minimal knot diagrams, J. Knot Theory Ramifications, 3, 1 (1994) 1-5.

Murakami, H., Some metrics on classical knots, in Knot Theory, Math. Ann., 20 (1) (1985) 35–45.

Jablan, S.V., Sazdanović, R., LinKnot – Knot Theory by Computer, World Scientific, New Jersey, London, Singapore (2007). http://math.ict.edu.rs/

Rolfsen, D., Knots and Links, Publish & Perish Inc., Berkeley (1976); American Mathematical Society, AMS Chelsea Publishing, 2003.

Conway, J., An enumeration of knots and links and some of their related properties, in Computational Problems in Abstract Algebra, ed. J. Leech, Proc. Conf. Oxford (1967); Pergamon Press, New York, 1970, 329–358.

Kauffman, L.H., Lambropoulou, S., On the classification of rational tangles, arXiv:math.GT/0311499v2

Kauffman, L.H., Lambropoulou, S., On the classification of rational knots, arXiv:math.GT/0212011v2

Schubert, H., Knoten mit zwei Brücken, Math. Zeit., 65 (1956) 133–170.

Darcy, I.K., Sumners, D.W., Applications of topology to DNA, in Knot Theory, (Eds.: V.F.R. Jones, J. Kania-Bartoszyńska, J.H. Przytycki, P. Traczyk, V.G. Turaev), Banach Center Publications, 42 (1998) 65–75.

Darcy, I., Strand passage metric table, http://homepage.math.uiowa.edu/idarcy/TAB/tabnov.pdf

Scharein, R., KnotPlot, http://www.knotplot.com/

Kawasaki, T., Java distance program, http://www.ma.utexas.edu/users/kawasaki/darcy/mainFr.html

Hart, P.E., Nilsson, N.J., Raphael, B., A Formal Basis for the Heuristic Determination of Minimum Cost Paths, IEEE Transactions on Systems Science and Cybernetics SSC4 4 (2) (1968) 100-107.

Haken, W., Theorie der Normalflächen, Acta Math., 105 (1961) 245–375.

Hemion, G., On the Classification of Homeomorphisms of 2-Manifolds and the Classification of 3-Manifolds, Acta Math., 142 (1979) 123–155.

Thistlethwaite, M., Knotscape 1.01 (1999). http://www.math.utk.edu/#morwen/knotscape.html

Musick, C., Recognizing trivial links in polynomial time, arXiv:1110.2871v3[math.GT]

Kronheimer, P.B., Mrowka, T.S., Khovanov homology is an unknot-detector, arXiv:1105.4346 [math.GT]

Moon, H., Calculating knot distances and solving tangle equations involving Montesinos tangles, dissertation, University of Iowa, http://ir.uiowa.edu/etd/859

Hoste, J., Nakanishi, Y., Taniyama, K., Unknotting Operations Involving Trivial Tangles, Osaka J. Math. 27 (1990) 555–566.

Abe, T., Kanenobu, T., Unoriented Band Surgery on Knots and Links, arXiv:1112.2449v1 [math.GT].

Kanenobu, T., H(2)-Gordian Distance of Knots, J. Knot Theory Ramifications, 20, 6 (2011) 813–835.

Bao, Y., H(2)-unknotting operation related to 2-bridge links, arXiv:1104.4435v1 [math.GT].

Miyazava, Y., Gordian distance and polynomial invariants, J. Knot Theory Ramifications, 6, 20 (2011) 895–907.

Jablan, S., Radovic, Lj., Unknotting numbers of alternating knots and link families, Publications de l’Institut Mathématique (to appear).

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Published

2015-02-01

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Research Articles