graphs, networks and algorithms 4th ed - d jungnickel (springer, 2013) ww

... the two vertices of odd degreeas start and end vertices. Let k = 1 and name the two vertices of odd degree a and b. By adding an (additional) edge ab to G, we get a connected multigraphH whose ... appeared.1See [Wil86 ]and[ BigLW76]. D. Jungnickel, Graphs, Networks and Algorithms, Algorithms and Computation in Mathematics 5,DOI 10.1007/97 8-3 -6 4 2-3 227 8-5 1, © Springer-Verlag Berlin Heidelberg 201312 ... called a walk;ifv0= vn, one speaks of a closedwalk.Awalkforwhichtheeiare distinct is called a trail,andaclosedwalkwith distinct edges is a closed trail. If, in addition, the vjare distinct,...