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_minimal_block(): D = DihedralGroup(6) block_system = D.minimal_block([0, 3]) for i in range(3): assert block_system[i] == block_system[i + 3] S = SymmetricGroup(6) assert S.minimal_block([0, 1]) == [0, 0, 0, 0, 0, 0] assert tetra.pgroup.minimal_block([0, 1]) == [0, 0, 0, 0]
def test_schreier_vector(): G = CyclicGroup(50) v = [0]*50 v[23] = -1 assert G.schreier_vector(23) == v H = DihedralGroup(8) assert H.schreier_vector(2) == [0, 1, -1, 0, 0, 1, 0, 0] L = SymmetricGroup(4) assert L.schreier_vector(1) == [1, -1, 0, 0]
def test_random_pr(): D = DihedralGroup(6) r = 11 n = 3 _random_prec_n = {} _random_prec_n[0] = {'s': 7, 't': 3, 'x': 2, 'e': -1} _random_prec_n[1] = {'s': 5, 't': 5, 'x': 1, 'e': -1} _random_prec_n[2] = {'s': 3, 't': 4, 'x': 2, 'e': 1} D._random_pr_init(r, n, _random_prec_n=_random_prec_n) assert D._random_gens[11] == [0, 1, 2, 3, 4, 5] _random_prec = {'s': 2, 't': 9, 'x': 1, 'e': -1} assert D.random_pr(_random_prec=_random_prec) == \ Permutation([0, 5, 4, 3, 2, 1])
def test_schreier_sims_random(): assert sorted(tetra.pgroup.base) == [0, 1] S = SymmetricGroup(3) base = [0, 1] strong_gens = [Permutation([1, 2, 0]), Permutation([1, 0, 2]), Permutation([0, 2, 1])] assert S.schreier_sims_random(base, strong_gens, 5) == (base, strong_gens) D = DihedralGroup(3) _random_prec = {'g': [Permutation([2, 0, 1]), Permutation([1, 2, 0]), Permutation([1, 0, 2])]} base = [0, 1] strong_gens = [Permutation([1, 2, 0]), Permutation([2, 1, 0]), Permutation([0, 2, 1])] assert D.schreier_sims_random([], D.generators, 2, _random_prec=_random_prec) == (base, strong_gens)
def test_strip(): D = DihedralGroup(5) D.schreier_sims() member = Permutation([4, 0, 1, 2, 3]) not_member1 = Permutation([0, 1, 4, 3, 2]) not_member2 = Permutation([3, 1, 4, 2, 0]) identity = Permutation([0, 1, 2, 3, 4]) res1 = _strip(member, D.base, D.basic_orbits, D.basic_transversals) res2 = _strip(not_member1, D.base, D.basic_orbits, D.basic_transversals) res3 = _strip(not_member2, D.base, D.basic_orbits, D.basic_transversals) assert res1[0] == identity assert res1[1] == len(D.base) + 1 assert res2[0] == not_member1 assert res2[1] == len(D.base) + 1 assert res3[0] != identity assert res3[1] == 2
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_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_direct_product_n(): C = CyclicGroup(4) D = DihedralGroup(4) G = DirectProduct(C, C, C) assert G.order() == 64 assert G.degree == 12 assert len(G.orbits()) == 3 assert G.is_abelian is True H = DirectProduct(D, C) assert H.order() == 32 assert H.is_abelian is False
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_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 test_DihedralGroup(): G = DihedralGroup(6) elements = list(G.generate()) assert len(elements) == 12 assert G.is_transitive() is True assert G.is_abelian is False assert G.is_solvable is True assert G.is_nilpotent is False H = DihedralGroup(1) assert H.order() == 2 L = DihedralGroup(2) assert L.order() == 4 assert L.is_abelian is True assert L.is_nilpotent is True
def test_orbit_rep(): G = DihedralGroup(6) assert G.orbit_rep(1, 3) in [Permutation([2, 3, 4, 5, 0, 1]), Permutation([4, 3, 2, 1, 0, 5])] H = CyclicGroup(4)*G assert H.orbit_rep(1, 5) is False