Appendix DHints for exercises
Hint for Exercise 1.1. See Section 1.4 and Conjecture 1.4.4.
Hint for Exercise 1.2. It is possible that the circuit decomposition of 2G may contain a digon, which corresponds to a single edge of the original graph G (not a circuit).
Hint for Exercise 1.3. The union of * and the symmetric difference of all members of * forms an even subgraph double cover of the graph. (See Definition A.2.3 for the definition ...