(1) Universidade Federal de Pernambuco, Recife, Brazil;(2) University of Massachusetts, 02125 Boston, MA, USA;(3) Department of Mathematics, United States Natal Academic, 21402 Annapolis, MD, USA
Abstract:
The classical Gauss code problem asks to characterize which cyclic sequences arise as the vertex sequence of the straight-ahead path of a 4-regular graph embedded in the plane This problem is generalized to certain 4 regular graphs in arbitrary surfacesA characterization is given for the existence of a 4-regular graph in a specified surface yielding the specified sequence This characterization is obtained using a generalization of Shank's left-right paths