=== Instance 2: the same GREEDY on a graphic matroid = Kruskal ===
  minimum spanning tree edges (in the order the weights fall):
    g-h(1) c-i(2) f-g(2) a-b(4) c-f(4) c-d(7) a-h(8) d-e(9)
  total weight = 37,  edges chosen = 8 (a spanning tree of 9 vertices needs 8)
