def test_is_alt_sym(): G = DihedralGroup(10) assert G.is_alt_sym() is False S = SymmetricGroup(10) N_eps = 10 _random_prec = {'N_eps': N_eps, 0: Permutation([[2], [1, 4], [0, 6, 7, 8, 9, 3, 5]]), 1: Permutation([[1, 8, 7, 6, 3, 5, 2, 9], [0, 4]]), 2: Permutation([[5, 8], [4, 7], [0, 1, 2, 3, 6, 9]]), 3: Permutation([[3], [0, 8, 2, 7, 4, 1, 6, 9, 5]]), 4: Permutation([[8], [4, 7, 9], [3, 6], [0, 5, 1, 2]]), 5: Permutation([[6], [0, 2, 4, 5, 1, 8, 3, 9, 7]]), 6: Permutation([[6, 9, 8], [4, 5], [1, 3, 7], [0, 2]]), 7: Permutation([[4], [0, 2, 9, 1, 3, 8, 6, 5, 7]]), 8: Permutation([[1, 5, 6, 3], [0, 2, 7, 8, 4, 9]]), 9: Permutation([[8], [6, 7], [2, 3, 4, 5], [0, 1, 9]])} assert S.is_alt_sym(_random_prec=_random_prec) is True A = AlternatingGroup(10) _random_prec = {'N_eps': N_eps, 0: Permutation([[1, 6, 4, 2, 7, 8, 5, 9, 3], [0]]), 1: Permutation([[1], [0, 5, 8, 4, 9, 2, 3, 6, 7]]), 2: Permutation([[1, 9, 8, 3, 2, 5], [0, 6, 7, 4]]), 3: Permutation([[6, 8, 9], [4, 5], [1, 3, 7, 2], [0]]), 4: Permutation([[8], [5], [4], [2, 6, 9, 3], [1], [0, 7]]), 5: Permutation([[3, 6], [0, 8, 1, 7, 5, 9, 4, 2]]), 6: Permutation([[5], [2, 9], [1, 8, 3], [0, 4, 7, 6]]), 7: Permutation([[1, 8, 4, 7, 2, 3], [0, 6, 9, 5]]), 8: Permutation([[5, 8, 7], [3], [1, 4, 2, 6], [0, 9]]), 9: Permutation([[4, 9, 6], [3, 8], [1, 2], [0, 5, 7]])} assert A.is_alt_sym(_random_prec=_random_prec) is False
def test_center(): # the center of the dihedral group D_n is of order 2 for even n for i in (4, 6, 10): D = DihedralGroup(i) assert (D.center()).order() == 2 # the center of the dihedral group D_n is of order 1 for odd n>2 for i in (3, 5, 7): D = DihedralGroup(i) assert (D.center()).order() == 1 # the center of an abelian group is the group itself for i in (2, 3, 5): for j in (1, 5, 7): for k in (1, 1, 11): G = AbelianGroup(i, j, k) assert G.center().is_subgroup(G) # the center of a nonabelian simple group is trivial for i in(1, 5, 9): A = AlternatingGroup(i) assert (A.center()).order() == 1 # brute-force verifications D = DihedralGroup(5) A = AlternatingGroup(3) C = CyclicGroup(4) G.is_subgroup(D*A*C) assert _verify_centralizer(G, G)
def test_commutator(): # the commutator of the trivial group and the trivial group is trivial S = SymmetricGroup(3) triv = PermutationGroup([Permutation([0, 1, 2])]) assert S.commutator(triv, triv).is_subgroup(triv) # the commutator of the trivial group and any other group is again trivial A = AlternatingGroup(3) assert S.commutator(triv, A).is_subgroup(triv) # the commutator is commutative for i in (3, 4, 5): S = SymmetricGroup(i) A = AlternatingGroup(i) D = DihedralGroup(i) assert S.commutator(A, D).is_subgroup(S.commutator(D, A)) # the commutator of an abelian group is trivial S = SymmetricGroup(7) A1 = AbelianGroup(2, 5) A2 = AbelianGroup(3, 4) triv = PermutationGroup([Permutation([0, 1, 2, 3, 4, 5, 6])]) assert S.commutator(A1, A1).is_subgroup(triv) assert S.commutator(A2, A2).is_subgroup(triv) # examples calculated by hand S = SymmetricGroup(3) A = AlternatingGroup(3) assert S.commutator(A, S).is_subgroup(A)
def test_PermutationGroup(): assert PermutationGroup() == PermutationGroup(Permutation()) a = Permutation(1, 2) b = Permutation(2, 3, 1) G = PermutationGroup(a, b, degree=5) assert G.contains(G[0]) A = AlternatingGroup(4) A.schreier_sims() assert A.base == [0, 1] assert A.basic_stabilizers == [ PermutationGroup(Permutation(0, 1, 2), Permutation(1, 2, 3)), PermutationGroup(Permutation(1, 2, 3)) ] D = DihedralGroup(12) assert D.is_primitive(randomized=False) is False D = DihedralGroup(10) assert D.is_primitive() is False p = Permutation(0, 1, 2, 3, 4, 5) G1 = PermutationGroup([Permutation(0, 1, 2), Permutation(0, 1)]) G2 = PermutationGroup([Permutation(0, 2), Permutation(0, 1, 2)]) G3 = PermutationGroup([p, p**2]) assert G1.order() == G2.order() == G3.order() == 6 assert G1.is_subgroup(G2) is True assert G1.is_subgroup(G3) is False a, b = [Permutation([1, 0, 3, 2]), Permutation([1, 3, 0, 2])] G = PermutationGroup([a, b]) assert G.make_perm([0, 1, 0]) == Permutation(0, 2, 3, 1) S = SymmetricGroup(5) base, strong_gens = S.schreier_sims_random() assert _verify_bsgs(S, base, strong_gens) D = DihedralGroup(4) assert D.strong_gens == [ Permutation(0, 1, 2, 3), Permutation(0, 3)(1, 2), Permutation(1, 3) ] a = Permutation([1, 2, 0]) b = Permutation([1, 0, 2]) G = PermutationGroup([a, b]) assert G.transitivity_degree == 3 a = Permutation([1, 2, 0, 4, 5, 6, 3]) G = PermutationGroup([a]) assert G.orbit(0) == {0, 1, 2} assert G.orbit([0, 4], 'union') == {0, 1, 2, 3, 4, 5, 6} assert G.orbit([0, 4], 'sets') == {(0, 3), (0, 4), (0, 5), (0, 6), (1, 3), (1, 4), (1, 5), (1, 6), (2, 3), (2, 4), (2, 5), (2, 6)} assert G.orbit([0, 4], 'tuples') == {(0, 3), (0, 4), (0, 5), (0, 6), (1, 3), (1, 4), (1, 5), (1, 6), (2, 3), (2, 4), (2, 5), (2, 6)}
def test_verify_normal_closure(): # verified by GAP S = SymmetricGroup(3) A = AlternatingGroup(3) assert _verify_normal_closure(S, A, closure=A) S = SymmetricGroup(5) A = AlternatingGroup(5) C = CyclicGroup(5) assert _verify_normal_closure(S, A, closure=A) assert _verify_normal_closure(S, C, closure=A)
def test_AlternatingGroup(): G = AlternatingGroup(5) elements = list(G.generate()) assert len(elements) == 60 assert [perm.is_even for perm in elements] == [True] * 60 H = AlternatingGroup(1) assert H.order() == 1 L = AlternatingGroup(2) assert L.order() == 1
def test_handle_precomputed_bsgs(): A = AlternatingGroup(5) A.schreier_sims() base = A.base strong_gens = A.strong_gens result = _handle_precomputed_bsgs(base, strong_gens) strong_gens_distr = _distribute_gens_by_base(base, strong_gens) assert strong_gens_distr == result[2] transversals = result[0] orbits = result[1] base_len = len(base) for i in range(base_len): for el in orbits[i]: assert transversals[i][el](base[i]) == el for j in range(i): assert transversals[i][el](base[j]) == base[j] order = 1 for i in range(base_len): order *= len(orbits[i]) assert A.order() == order _, transversals = _orbits_transversals_from_bsgs(base, strong_gens_distr) assert transversals == _handle_precomputed_bsgs(base, strong_gens, transversals)[0] assert transversals == _handle_precomputed_bsgs( base, strong_gens, transversals, basic_orbits=transversals, strong_gens_distr=strong_gens_distr)[0] D = DihedralGroup(3) D.schreier_sims() assert (_handle_precomputed_bsgs(D.base, D.strong_gens, basic_orbits=D.basic_orbits) == ([{ 0: Permutation(2), 1: Permutation(0, 1, 2), 2: Permutation(0, 2) }, { 1: Permutation(2), 2: Permutation(1, 2) }], [[0, 1, 2], [1, 2]], [[ Permutation(0, 1, 2), Permutation(0, 2), Permutation(1, 2) ], [Permutation(1, 2)]]))
def test_lower_central_series(): # the lower central series of the trivial group consists of the trivial # group triv = PermutationGroup([Permutation([0, 1, 2])]) assert triv.lower_central_series()[0].is_subgroup(triv) # the lower central series of a simple group consists of the group itself for i in (5, 6, 7): A = AlternatingGroup(i) assert A.lower_central_series()[0].is_subgroup(A) # GAP-verified example S = SymmetricGroup(6) series = S.lower_central_series() assert len(series) == 2 assert series[1].is_subgroup(AlternatingGroup(6))
def test_derived_series(): # the derived series of the trivial group consists only of the trivial group triv = PermutationGroup([Permutation([0, 1, 2])]) assert triv.derived_series()[0].is_subgroup(triv) # the derived series for a simple group consists only of the group itself for i in (5, 6, 7): A = AlternatingGroup(i) assert A.derived_series()[0].is_subgroup(A) # the derived series for S_4 is S_4 > A_4 > K_4 > triv S = SymmetricGroup(4) series = S.derived_series() assert series[1].is_subgroup(AlternatingGroup(4)) assert series[2].is_subgroup(DihedralGroup(2)) assert series[3].is_trivial
def test_verify_centralizer(): # verified by GAP S = SymmetricGroup(3) A = AlternatingGroup(3) triv = PermutationGroup([Permutation([0, 1, 2])]) assert _verify_centralizer(S, S, centr=triv) assert _verify_centralizer(S, A, centr=A)
def test_remove_gens(): S = SymmetricGroup(10) base, strong_gens = S.schreier_sims_incremental() new_gens = _remove_gens(base, strong_gens) assert _verify_bsgs(S, base, new_gens) is True A = AlternatingGroup(7) base, strong_gens = A.schreier_sims_incremental() new_gens = _remove_gens(base, strong_gens) assert _verify_bsgs(A, base, new_gens) is True D = DihedralGroup(2) base, strong_gens = D.schreier_sims_incremental() new_gens = _remove_gens(base, strong_gens) assert _verify_bsgs(D, base, new_gens) is True D = DihedralGroup(2) base, strong_gens = D.schreier_sims_incremental() strong_gens_distr = _distribute_gens_by_base(base, strong_gens) _, transversals = _orbits_transversals_from_bsgs(base, strong_gens_distr) new_gens = _remove_gens(base, strong_gens, transversals, strong_gens_distr) assert _verify_bsgs(D, base, new_gens) is True
def test_is_nilpotent(): # every abelian group is nilpotent for i in (1, 2, 3): C = CyclicGroup(i) Ab = AbelianGroup(i, i + 2) assert C.is_nilpotent assert Ab.is_nilpotent Ab = AbelianGroup(5, 7, 10) assert Ab.is_nilpotent # A_5 is not solvable and thus not nilpotent assert AlternatingGroup(5).is_nilpotent is False
def test_normal_closure(): # the normal closure of the trivial group is trivial S = SymmetricGroup(3) identity = Permutation([0, 1, 2]) closure = S.normal_closure(identity) assert closure.is_trivial # the normal closure of the entire group is the entire group A = AlternatingGroup(4) assert A.normal_closure(A).is_subgroup(A) # brute-force verifications for subgroups for i in (3, 4, 5): S = SymmetricGroup(i) A = AlternatingGroup(i) D = DihedralGroup(i) C = CyclicGroup(i) for gp in (A, D, C): assert _verify_normal_closure(S, gp) # brute-force verifications for all elements of a group for i in range(10): S = SymmetricGroup(5) elements = list(S.generate_dimino()) for element in elements: assert _verify_normal_closure(S, element) # small groups small = [] for i in (1, 2, 3): small.append(SymmetricGroup(i)) small.append(AlternatingGroup(i)) small.append(DihedralGroup(i)) small.append(CyclicGroup(i)) for gp in small: for gp2 in small: if gp2.is_subgroup(gp, 0) and gp2.degree == gp.degree: assert _verify_normal_closure(gp, gp2)
def test_centralizer(): # the centralizer of the trivial group is the entire group S = SymmetricGroup(2) assert S.centralizer(Permutation(list(range(2)))).is_subgroup(S) A = AlternatingGroup(5) assert A.centralizer(Permutation(list(range(5)))).is_subgroup(A) # a centralizer in the trivial group is the trivial group itself triv = PermutationGroup([Permutation([0, 1, 2, 3])]) D = DihedralGroup(4) assert triv.centralizer(D).is_subgroup(triv) # brute-force verifications for centralizers of groups for i in (4, 5, 6): S = SymmetricGroup(i) A = AlternatingGroup(i) C = CyclicGroup(i) D = DihedralGroup(i) for gp in (S, A, C, D): for gp2 in (S, A, C, D): if not gp2.is_subgroup(gp): assert _verify_centralizer(gp, gp2) # verify the centralizer for all elements of several groups S = SymmetricGroup(5) elements = list(S.generate_dimino()) for element in elements: assert _verify_centralizer(S, element) A = AlternatingGroup(5) elements = list(A.generate_dimino()) for element in elements: assert _verify_centralizer(A, element) D = DihedralGroup(7) elements = list(D.generate_dimino()) for element in elements: assert _verify_centralizer(D, element) # verify centralizers of small groups within small groups small = [] for i in (1, 2, 3): small.append(SymmetricGroup(i)) small.append(AlternatingGroup(i)) small.append(DihedralGroup(i)) small.append(CyclicGroup(i)) for gp in small: for gp2 in small: if gp.degree == gp2.degree: assert _verify_centralizer(gp, gp2)
def test_schreier_sims_incremental(): identity = Permutation([0, 1, 2, 3, 4]) TrivialGroup = PermutationGroup([identity]) base, strong_gens = TrivialGroup.schreier_sims_incremental(base=[0, 1, 2]) assert _verify_bsgs(TrivialGroup, base, strong_gens) is True S = SymmetricGroup(5) base, strong_gens = S.schreier_sims_incremental(base=[0, 1, 2]) assert _verify_bsgs(S, base, strong_gens) is True D = DihedralGroup(2) base, strong_gens = D.schreier_sims_incremental(base=[1]) assert _verify_bsgs(D, base, strong_gens) is True A = AlternatingGroup(7) gens = A.generators[:] gen0 = gens[0] gen1 = gens[1] gen1 = rmul(gen1, ~gen0) gen0 = rmul(gen0, gen1) gen1 = rmul(gen0, gen1) base, strong_gens = A.schreier_sims_incremental(base=[0, 1], gens=gens) assert _verify_bsgs(A, base, strong_gens) is True C = CyclicGroup(11) gen = C.generators[0] base, strong_gens = C.schreier_sims_incremental(gens=[gen**3]) assert _verify_bsgs(C, base, strong_gens) is True
def _subgroup_search(i, j, k): def prop_true(x): return True def prop_fix_points(x): return [x(point) for point in points] == points def prop_comm_g(x): return rmul(x, g) == rmul(g, x) def prop_even(x): return x.is_even for i in range(i, j, k): S = SymmetricGroup(i) A = AlternatingGroup(i) C = CyclicGroup(i) Sym = S.subgroup_search(prop_true) assert Sym.is_subgroup(S) Alt = S.subgroup_search(prop_even) assert Alt.is_subgroup(A) Sym = S.subgroup_search(prop_true, init_subgroup=C) assert Sym.is_subgroup(S) points = [7] assert S.stabilizer(7).is_subgroup(S.subgroup_search(prop_fix_points)) points = [3, 4] assert S.stabilizer(3).stabilizer(4).is_subgroup( S.subgroup_search(prop_fix_points)) points = [3, 5] fix35 = A.subgroup_search(prop_fix_points) points = [5] fix5 = A.subgroup_search(prop_fix_points) assert A.subgroup_search(prop_fix_points, init_subgroup=fix35).is_subgroup(fix5) base, strong_gens = A.schreier_sims_incremental() g = A.generators[0] comm_g = \ A.subgroup_search(prop_comm_g, base=base, strong_gens=strong_gens) assert _verify_bsgs(comm_g, base, comm_g.generators) is True assert [prop_comm_g(gen) is True for gen in comm_g.generators]
def test_naive_list_centralizer(): # verified by GAP S = SymmetricGroup(3) A = AlternatingGroup(3) assert _naive_list_centralizer(S, S) == [Permutation([0, 1, 2])] assert PermutationGroup(_naive_list_centralizer(S, A)).is_subgroup(A)