Do for discussion on Mon. 3/22:
## HH1(a), HH2(a).
Do for discussion on Wed. 3/24:
## HH1 and HH2: in each, do one or two of (b,c,d).
# HH3.
HH1. Use the proof method of Theorem 3.2.4 to decompose into subgraphs isomorphic to P3 :
HH2. Use the proof method of Theorem 3.1.7 (Listing's Theorem) to decompose into the smallest possible number of trails:
HH3. Do your best to give a correct proof that, in the infinite graph G shown here, each of the three lobes hanging off vertex x has a 1-way Eulerian trail. (All the lobes are the same, but I only drew a large part of one of them.)