i1 : D = digraph({{a, {b,c}}, {b,{d,e}}, {c, {e,h}}, {d, {f}}, {e, {f,g}}, {f, {}}, {g, {}}, {h, {}}}) o1 = Digraph{a => set {b, c}} b => set {d, e} c => set {e, h} d => set {f} e => set {f, g} f => set {} g => set {} h => set {} o1 : Digraph |
i2 : pA = parents(D,e) o2 = set {b, c} o2 : Set |