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_stabilizer(): S = SymmetricGroup(2) H = S.stabilizer(0) assert H.generators == [Permutation(1)] a = Permutation([2, 0, 1, 3, 4, 5]) b = Permutation([2, 1, 3, 4, 5, 0]) G = PermutationGroup([a, b]) G0 = G.stabilizer(0) assert G0.order() == 60 gens_cube = [[1, 3, 5, 7, 0, 2, 4, 6], [1, 3, 0, 2, 5, 7, 4, 6]] gens = [Permutation(p) for p in gens_cube] G = PermutationGroup(gens) G2 = G.stabilizer(2) assert G2.order() == 6 G2_1 = G2.stabilizer(1) v = list(G2_1.generate(af=True)) assert v == [[0, 1, 2, 3, 4, 5, 6, 7], [3, 1, 2, 0, 7, 5, 6, 4]] gens = ( (1, 2, 0, 4, 5, 3, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19), (0, 1, 2, 3, 4, 5, 19, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 7, 17, 18), (0, 1, 2, 3, 4, 5, 6, 7, 9, 18, 16, 11, 12, 13, 14, 15, 8, 17, 10, 19)) gens = [Permutation(p) for p in gens] G = PermutationGroup(gens) G2 = G.stabilizer(2) assert G2.order() == 181440 S = SymmetricGroup(3) assert [G.order() for G in S.basic_stabilizers] == [6, 2]
def test_transitivity_degree(): perm = Permutation([1, 2, 0]) C = PermutationGroup([perm]) assert C.transitivity_degree == 1 gen1 = Permutation([1, 2, 0, 3, 4]) gen2 = Permutation([1, 2, 3, 4, 0]) # alternating group of degree 5 Alt = PermutationGroup([gen1, gen2]) assert Alt.transitivity_degree == 3
def test_is_solvable(): a = Permutation([1, 2, 0]) b = Permutation([1, 0, 2]) G = PermutationGroup([a, b]) assert G.is_solvable a = Permutation([1, 2, 3, 4, 0]) b = Permutation([1, 0, 2, 3, 4]) G = PermutationGroup([a, b]) assert not G.is_solvable
def test_equality(): p_1 = Permutation(0, 1, 3) p_2 = Permutation(0, 2, 3) p_3 = Permutation(0, 1, 2) p_4 = Permutation(0, 1, 3) g_1 = PermutationGroup(p_1, p_2) g_2 = PermutationGroup(p_3, p_4) g_3 = PermutationGroup(p_2, p_1) assert g_1 == g_2 assert g_1.generators != g_2.generators assert g_1 == g_3
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_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_rubik(): G = PermutationGroup(rubik_cube_generators()) assert G.order() == 43252003274489856000 G1 = PermutationGroup(G[:3]) assert G1.order() == 170659735142400 assert not G1.is_normal(G) G2 = G.normal_closure(G1.generators) assert G2.is_subgroup(G)
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_has(): a = Permutation([1, 0]) G = PermutationGroup([a]) assert G.is_abelian a = Permutation([2, 0, 1]) b = Permutation([2, 1, 0]) G = PermutationGroup([a, b]) assert not G.is_abelian G = PermutationGroup([a]) assert G.has(a) assert not G.has(b) a = Permutation([2, 0, 1, 3, 4, 5]) b = Permutation([0, 2, 1, 3, 4]) assert PermutationGroup(a, b).degree == \ PermutationGroup(a, b).degree == 6
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_coset_rank(): gens_cube = [[1, 3, 5, 7, 0, 2, 4, 6], [1, 3, 0, 2, 5, 7, 4, 6]] gens = [Permutation(p) for p in gens_cube] G = PermutationGroup(gens) i = 0 for h in G.generate(af=True): rk = G.coset_rank(h) assert rk == i h1 = G.coset_unrank(rk, af=True) assert h == h1 i += 1 assert G.coset_unrank(48) is None assert G.coset_unrank(G.coset_rank(gens[0])) == gens[0]
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_derived_subgroup(): a = Permutation([1, 0, 2, 4, 3]) b = Permutation([0, 1, 3, 2, 4]) G = PermutationGroup([a, b]) C = G.derived_subgroup() assert C.order() == 3 assert C.is_normal(G) assert C.is_subgroup(G, 0) assert not G.is_subgroup(C, 0) gens_cube = [[1, 3, 5, 7, 0, 2, 4, 6], [1, 3, 0, 2, 5, 7, 4, 6]] gens = [Permutation(p) for p in gens_cube] G = PermutationGroup(gens) C = G.derived_subgroup() assert C.order() == 12
def test_rubik1(): gens = rubik_cube_generators() gens1 = [gens[-1]] + [p**2 for p in gens[1:]] G1 = PermutationGroup(gens1) assert G1.order() == 19508428800 gens2 = [p**2 for p in gens] G2 = PermutationGroup(gens2) assert G2.order() == 663552 assert G2.is_subgroup(G1, 0) C1 = G1.derived_subgroup() assert C1.order() == 4877107200 assert C1.is_subgroup(G1, 0) assert not G2.is_subgroup(C1, 0) G = RubikGroup(2) assert G.order() == 3674160 pytest.raises(ValueError, lambda: RubikGroup(0)) pytest.raises(ValueError, lambda: rubik(1)) G = RubikGroup(3) assert G.order() == 43252003274489856000
def test_generate(): a = Permutation([1, 0]) g = list(PermutationGroup([a]).generate()) assert g == [Permutation([0, 1]), Permutation([1, 0])] assert len(list(PermutationGroup(Permutation((0, 1))).generate())) == 1 g = PermutationGroup([a]).generate(method='dimino') assert list(g) == [Permutation([0, 1]), Permutation([1, 0])] a = Permutation([2, 0, 1]) b = Permutation([2, 1, 0]) G = PermutationGroup([a, b]) g = G.generate() v1 = [p.array_form for p in list(g)] v1.sort() assert v1 == [[0, 1, 2], [0, 2, 1], [1, 0, 2], [1, 2, 0], [2, 0, 1], [2, 1, 0]] v2 = list(G.generate(method='dimino', af=True)) assert v1 == sorted(v2) a = Permutation([2, 0, 1, 3, 4, 5]) b = Permutation([2, 1, 3, 4, 5, 0]) g = PermutationGroup([a, b]).generate(af=True) assert len(list(g)) == 360
def test_eq(): a = [[1, 2, 0, 3, 4, 5], [1, 0, 2, 3, 4, 5], [2, 1, 0, 3, 4, 5], [ 1, 2, 0, 3, 4, 5]] a = [Permutation(p) for p in a + [[1, 2, 3, 4, 5, 0]]] g = Permutation([1, 2, 3, 4, 5, 0]) G1, G2, G3 = [PermutationGroup(x) for x in [a[:2], a[2:4], [g, g**2]]] assert G1.order() == G2.order() == G3.order() == 6 assert G1.is_subgroup(G2) assert not G1.is_subgroup(G3) G4 = PermutationGroup([Permutation([0, 1])]) assert not G1.is_subgroup(G4) assert G4.is_subgroup(G1, 0) assert PermutationGroup(g, g).is_subgroup(PermutationGroup(g)) assert SymmetricGroup(3).is_subgroup(SymmetricGroup(4), 0) assert SymmetricGroup(3).is_subgroup(SymmetricGroup(3)*CyclicGroup(5), 0) assert not CyclicGroup(5).is_subgroup(SymmetricGroup(3)*CyclicGroup(5), 0) assert CyclicGroup(3).is_subgroup(SymmetricGroup(3)*CyclicGroup(5), 0)
def check(h, size, rpt, target): assert len(h.faces) + len(h.vertices) - len(h.edges) == 2 assert h.size == size got = set() for p in h.pgroup: # make sure it restores original P = h.copy() hit = P.corners for _ in range(rpt): P.rotate(p) if P.corners == hit: break else: print('error in permutation', p.array_form) for _ in range(rpt): P.rotate(p) got.add(tuple(P.corners)) c = P.corners f = [[c[i] for i in f] for f in P.faces] assert h.faces == Polyhedron(c, f).faces assert len(got) == target assert PermutationGroup([Permutation(g) for g in got]).is_group
def test_coset_factor(): a = Permutation([0, 2, 1]) G = PermutationGroup([a]) c = Permutation([2, 1, 0]) assert not G.coset_factor(c) assert G.coset_rank(c) is None a = Permutation([2, 0, 1, 3, 4, 5]) b = Permutation([2, 1, 3, 4, 5, 0]) g = PermutationGroup([a, b]) assert g.order() == 360 d = Permutation([1, 0, 2, 3, 4, 5]) assert not g.coset_factor(d.array_form) assert not g.contains(d) assert Permutation(2) in G c = Permutation([1, 0, 2, 3, 5, 4]) v = g.coset_factor(c, True) tr = g.basic_transversals p = Permutation.rmul(*[tr[i][v[i]] for i in range(len(g.base))]) assert p == c v = g.coset_factor(c) p = Permutation.rmul(*v) assert p == c assert g.contains(c) G = PermutationGroup([Permutation([2, 1, 0])]) p = Permutation([1, 0, 2]) assert G.coset_factor(p) == []
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)
def test_is_group(): assert PermutationGroup(Permutation(1, 2), Permutation(2, 4)).is_group is True assert SymmetricGroup(4).is_group is True
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(consec_succ=5) 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}
def test_elements(): p = Permutation(2, 3) assert PermutationGroup(p).elements == {Permutation(3), Permutation(2, 3)}
def test_is_trivial(): for i in range(5): triv = PermutationGroup([Permutation(list(range(i)))]) assert triv.is_trivial
def test_orbits(): a = Permutation([2, 0, 1]) b = Permutation([2, 1, 0]) g = PermutationGroup([a, b]) assert g.orbit(0) == {0, 1, 2} assert g.orbits() == [{0, 1, 2}] assert g.is_transitive() and g.is_transitive(strict=False) assert g.orbit_transversal(0) == \ [Permutation( [0, 1, 2]), Permutation([2, 0, 1]), Permutation([1, 2, 0])] assert g.orbit_transversal(0, True) == \ [(0, Permutation([0, 1, 2])), (2, Permutation([2, 0, 1])), (1, Permutation([1, 2, 0]))] a = Permutation(list(range(1, 100)) + [0]) G = PermutationGroup([a]) assert [min(o) for o in G.orbits()] == [0] G = PermutationGroup(rubik_cube_generators()) assert [min(o) for o in G.orbits()] == [0, 1] assert not G.is_transitive() and not G.is_transitive(strict=False) G = PermutationGroup([Permutation(0, 1, 3), Permutation(3)(0, 1)]) assert not G.is_transitive() and G.is_transitive(strict=False) assert PermutationGroup( Permutation(3)).is_transitive(strict=False) is False
def test_is_normal(): gens_s5 = [Permutation(p) for p in [[1, 2, 3, 4, 0], [2, 1, 4, 0, 3]]] G1 = PermutationGroup(gens_s5) assert G1.order() == 120 gens_a5 = [Permutation(p) for p in [[1, 0, 3, 2, 4], [2, 1, 4, 3, 0]]] G2 = PermutationGroup(gens_a5) assert G2.order() == 60 assert G2.is_normal(G1) gens3 = [Permutation(p) for p in [[2, 1, 3, 0, 4], [1, 2, 0, 3, 4]]] G3 = PermutationGroup(gens3) assert not G3.is_normal(G1) assert G3.order() == 12 G4 = G1.normal_closure(G3.generators) assert G4.order() == 60 gens5 = [Permutation(p) for p in [[1, 2, 3, 0, 4], [1, 2, 0, 3, 4]]] G5 = PermutationGroup(gens5) assert G5.order() == 24 G6 = G1.normal_closure(G5.generators) assert G6.order() == 120 assert G1.is_subgroup(G6) assert not G1.is_subgroup(G4) assert G2.is_subgroup(G4) s4 = PermutationGroup(Permutation(0, 1, 2, 3), Permutation(3)(0, 1)) s6 = PermutationGroup(Permutation(0, 1, 2, 3, 5), Permutation(5)(0, 1)) assert s6.is_normal(s4, strict=False) assert not s4.is_normal(s6, strict=False)
def test_order(): a = Permutation([2, 0, 1, 3, 4, 5, 6, 7, 8, 9]) b = Permutation([2, 1, 3, 4, 5, 6, 7, 8, 9, 0]) g = PermutationGroup([a, b]) assert g.order() == 1814400 assert PermutationGroup().order() == 1