Generating \(4\)-regular Hamiltonian Plane Graphs

O. Ascigil1, Y. Diao2, C. Erns3, D. High4, U. Ziegler5
1Department of Computer Science University of Kentucky Lexington, KY 40506
2Department of Mathematics University of North Carolina at Charlotte, Charlotte, NC 28223,
3Department of Mathematics Western Kentucky University Bowling Green, KY 42101
4Department of Mathematics Western Kentucky University Bowling Green, KY 42101,
5Department of Computer Science Western Kentucky University Bowling Green, KY 42101

Abstract

This paper describes the study of a special class of 4-regular plane graphs that are Hamiltonian. These graphs are of particular interest in knot theory. An algorithm is presented that randomly generates such graphs with \( n \) vertices with a fixed (and oriented) Hamiltonian cycle in \( O(n) \) time. An exact count of the number of such graphs with \( n \) vertices is obtained, and the asymptotic growth rate of this number is determined. Numerical evidence is provided to show that the algorithm can be modified to generate these graphs with a near uniform probability. This can be considered a first step in generating large random knots without bias.