theorem 22.1.

Let G be a connected graph.Then G is orientable if and only if each edge of G is contained in at least one cycle.

22.5 (i) Without using Theorem 22.1, prove that every Hamiltonian graph is orientable. (ii) Show, by finding an orientation for each, that Kn (n 2 3) and Krs (r, s 2 2) are orientable. iii) Find orientations for the Petersen graph and the graph of the dodecahedron. 22 68 In the above scheduling problem, calculate the latest times at which we can reach the