Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-28T14:28:18.816Z Has data issue: false hasContentIssue false

Total curvature, ropelength and crossing number of thick knots

Published online by Cambridge University Press:  01 July 2007

Y. DIAO
Affiliation:
Department of Mathematics and Statistics, University of North Carolina Charlotte, Charlotte, NC 28223, U.S.A. e-mail: [email protected]
C. ERNST
Affiliation:
Department of Mathematics, Western Kentucky University, Bowling Green, KY 42101, U.S.A. e-mail: [email protected]

Abstract

We first study the minimum total curvature of a knot when it is embedded on the cubic lattice. Let be a knot or link with a lattice embedding of minimum total curvature among all possible lattice embeddings of . We show that there exist positive constants c1 and c2 such that for any knot type . Furthermore we show that the powers of in the above inequalities are sharp hence cannot be improved in general. Our results and observations show that lattice embeddings with minimum total curvature are quite different from those with minimum or near minimum lattice embedding length. In addition, we discuss the relationship between minimal total curvature and minimal ropelength for a given knot type. At the end of the paper, we study the total curvatures of smooth thick knots and show that there are some essential differences between the total curvatures of smooth thick knots and lattice knots.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1]Burde, G. and Zieschang, H.. Knots (de Gruyter, Berlin, 1986).Google Scholar
[2]Boileau, M. and Zieschang, H.. Nombre de ponts et générateurs méridiens des entrelacs de Montesinos. Comment. Math. Helv. 60 (1985), 270279.CrossRefGoogle Scholar
[3]Buck, G.. Four-thirds power law for knots and links. Nature 392 (1998), 238239.CrossRefGoogle Scholar
[4]Buck, G. and Simon, J.. Thickness and crossing number of knots. Topology Appl. 91 (3) (1999), 245257.Google Scholar
[5]Buck, G. and Simon, J.. Total curvature and packing of knots. Topology Appl. 154 (1) (2007), 192204.CrossRefGoogle Scholar
[6]Cantarella, J., Kusner, R. B. and Sullivan, J. M.. On the minimum ropelength of knots and links. Invent. Math. 150 (2002), 257286.CrossRefGoogle Scholar
[7]des Cloizeaux, J. and Mehta, M. L.. Topological constraints on polymer rings and critical indices. J. de Physique 40 (1979), 665670.CrossRefGoogle Scholar
[8]Diao, Y.. Minimal knotted polygons on the cubic lattice. J. Knot Theory Ramifications 2 (1993), 413425.Google Scholar
[9]Diao, Y.. The additivity of crossing numbers. J. Knot Theory Ramifications 13 (2004), 857866.CrossRefGoogle Scholar
[10]Diao, Y. and Ernst, C.. The complexity of lattice knots. Topology Appl. 90 (1) (1998), 19.CrossRefGoogle Scholar
[11]Diao, Y. and Ernst, C.. Realizable powers of ropelength by non-trivial knot families. J. Geometry and Topology 2 (2) (2004), 197208.Google Scholar
[12]Diao, Y. and Ernst, C.. Ropelengths of closed braids. Topology Appl. 154 (2) (2007), 491501.Google Scholar
[13]Diao, Y., Ernst, C. and Janse van Rensburg, E. J.. Thicknesses of knots. Math. Proc. Camb. Phil. Soc. 126 (1999), 293310.CrossRefGoogle Scholar
[14]Diao, Y., Ernst, C. and Thistlethwaite, M.. The linear growth in the length of a family of thick knots. J. Knot Theory Ramifications 12 (2003), 709715.Google Scholar
[15]Diao, Y., Ernst, C. and Yu, X.. Hamiltonian knot projections and lengths of thick knots. Topology Appl. 136 (2004), 736.CrossRefGoogle Scholar
[16]Delbrück, M.. Knotting problems in biology. Proc. Symp. Appl. Math. 14 (American Mathematical Society, 1962), 5563.CrossRefGoogle Scholar
[17]Edwards, S. F.. Statistical mechanics with topological constraints I. Proc. Phys. Soc. 91 (1967), 513519.CrossRefGoogle Scholar
[18]Edwards, S. F.. Statistical mechanics with topological constraints II. J. Phys. A (Proc. Phys. Soc.) 1 (1968), 1528.CrossRefGoogle Scholar
[19]Ernst, C. and Phipps, M.. A minimal link on the cubic lattice A. J. Knot Theory Ramifications 11 (2002), 165172.Google Scholar
[20]Frisch, H. L. and Klempner, D.. Topological isomerism and macromolecules. Advances in Macromolecular Chemistry V2. Pasika, W. M., ed. (Academic Press, 1970).Google Scholar
[21]Frisch, H. L. and Wasserman, E.. Chemical topology. J. Amer. Chem. Soc. 83 (1961), 37893795.Google Scholar
[22]Litherland, R., Simon, J., Durumeric, O. and Rawdon, E.. Thickness of knots. Topology Appl. 91 (3) (1999), 233244.CrossRefGoogle Scholar
[23]Milnor, J. W.. On the total curvature of knots. Ann. of Math. 52 (2) (1950), 248257.CrossRefGoogle Scholar
[24]Murasugi, K.. Knot Theory and Its Applications (Birkhäuser, 1996).Google Scholar
[25]Rawdon, E. and Simon, J.. The Möbius energy of thick knots. Topology Appl. 125 (1) (2002), 97109.CrossRefGoogle Scholar
[26]Janse van Rensburg, E. J. and Promislow, S. D.. The curvature of lattice knots. J. Knot Theory Ramifications 8 (1999), 463490.CrossRefGoogle Scholar
[27]Rolfsen, D.. Knots and Links, 2nd ed. Math. Lect. Ser., 7 (Publish or Perish, Inc., 1990).Google Scholar