from sympy.combinatorics.permutations import Permutation from sympy.combinatorics.named_groups import SymmetricGroup, AlternatingGroup, DihedralGroup from sympy.matrices import Matrix def test_pc_presentation(): Groups = [SymmetricGroup(3), SymmetricGroup(4), SymmetricGroup(9).sylow_subgroup(3), SymmetricGroup(9).sylow_subgroup(2), SymmetricGroup(8).sylow_subgroup(2), DihedralGroup(10)] S = SymmetricGroup(125).sylow_subgroup(5) G = S.derived_series()[2] Groups.append(G) G = SymmetricGroup(25).sylow_subgroup(5) Groups.append(G) S = SymmetricGroup(11**2).sylow_subgroup(11) G = S.derived_series()[2] Groups.append(G) for G in Groups: PcGroup = G.polycyclic_group() collector = PcGroup.collector pc_presentation = collector.pc_presentation pcgs = PcGroup.pcgs free_group = collector.free_group free_to_perm = {} for s, g in zip(free_group.symbols, pcgs): free_to_perm[s] = g for k, v in pc_presentation.items(): k_array = k.array_form if v != (): v_array = v.array_form lhs = Permutation() for gen in k_array: s = gen[0] e = gen[1] lhs = lhs*free_to_perm[s]**e if v == (): assert lhs.is_identity continue rhs = Permutation() for gen in v_array: s = gen[0] e = gen[1] rhs = rhs*free_to_perm[s]**e assert lhs == rhs def test_exponent_vector(): Groups = [SymmetricGroup(3), SymmetricGroup(4), SymmetricGroup(9).sylow_subgroup(3), SymmetricGroup(9).sylow_subgroup(2), SymmetricGroup(8).sylow_subgroup(2)] for G in Groups: PcGroup = G.polycyclic_group() collector = PcGroup.collector pcgs = PcGroup.pcgs # free_group = collector.free_group for gen in G.generators: exp = collector.exponent_vector(gen) g = Permutation() for i in range(len(exp)): g = g*pcgs[i]**exp[i] if exp[i] else g assert g == gen def test_induced_pcgs(): G = [SymmetricGroup(9).sylow_subgroup(3), SymmetricGroup(20).sylow_subgroup(2), AlternatingGroup(4), DihedralGroup(4), DihedralGroup(10), DihedralGroup(9), SymmetricGroup(3), SymmetricGroup(4)] for g in G: PcGroup = g.polycyclic_group() collector = PcGroup.collector gens = [gen for gen in g.generators] ipcgs = collector.induced_pcgs(gens) m = [] for i in ipcgs: m.append(collector.exponent_vector(i)) assert Matrix(m).is_upper