Towards Crossing-Free Hamiltonian Cycles in Simple Drawings of Complete Graphs

It is a longstanding conjecture that every simple drawing of a complete graph on $n\ge 3$ vertices contains a crossing-free Hamiltonian cycle. We strengthen this conjecture to “there exists a crossing-free Hamiltonian path between each pair of vertices” and show that this stronger conjecture holds for several classes of simple drawings, including strongly c-monotone drawings and cylindrical drawings. As a second main contribution, we give an overview on different classes of simple drawings and investigate inclusion relations between them up to weak isomorphism.