Are the following Boolean conjunctive queries cyclic or acyclic?
(a) a(A,B) Λ b(C,B) Λ c(D,B) Λ d(B,E) Λ e(E,F) Λ f(E,G) Λ g(E,H).
(b) a(A,B,C) Λ b(A,B,D) Λ c(C,D) Λ d(A,B,C,D).
(c) a(A,B,C) Λ b(A,B,D) Λ c(C,D) Λ d(C,E,F) Λ e(D,E,F).
If they are acyclic, give a join tree, if they are cyclic; give a hypertree decomposition of minimal width of the query.