Gauss diagrams as cubic graphs: The choice of the Hamiltonian cycle matters

Abstract

We explore to what extent the properties of a Gauss diagram are affected by the choice of its Hamiltonian cycle. We present an example of a realizable Gauss diagram and an unrealizable Gauss diagram that differ only by a choice of the Hamiltonian cycle. We present an example of two Gauss diagrams that correspond to different curves and differ only by a choice of the Hamiltonian cycle. We prove that a certain natural type of change of the Hamiltonian cycle preserves the realizability of the Gauss diagram.