“…The generators µ 1 5 , µ 2 5 , µ 3 5 , µ 4 5 correspond to these paths. Also for a ≥ 6 the 1-dimensional ∂-cycles in Γ(µ 2 , µ 3 , µ 1 5 , µ 2 5 , µ 3 5 , µ 4 5 )(a) 1 are given by closed edge paths of even length in the associahedron K a but one can show that they are all generated by the squares and the images of the paths as in Figure 5 under the face inclusions K 5 ֒→ K a . Therefore (Γ(µ 2 , µ 3 , µ 1 5 , µ 2 5 , µ 3 5 , µ 4 5 ), ∂) is acyclic in degree 1, so µ 1 5 , µ 2 5 , µ 3 5 , µ 4 5 are the only degree two generators of the minimal model of Ass.…”