Quelle bugfix.tst
Sprache: unbekannt
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gap> START_TEST("Test for various former bugs");
#
gap> # The following used to trigger an error starting with:
gap> # "SolutionMat: matrix and vector incompatible called from"
gap> K:=AbelianPcpGroup([3,3,3]);;
gap> A:=Subgroup(K,[K.1]);;
gap> cr:=CRRecordBySubgroup(K,A);;
gap> ExtensionsCR(cr);;
#
# Comparing homomorphisms used to be broken
gap> K:=AbelianPcpGroup(1,[3]);;
gap> hom1:=GroupHomomorphismByImages(K,K,[K.1],[K.1]);;
gap> hom2:=GroupHomomorphismByImages(K,K,[K.1^2],[K.1^2]);;
gap> hom1=hom2;
true
gap> hom1=IdentityMapping(K);
true
gap> hom2=IdentityMapping(K);
true
#
gap> # The following incorrectly triggered an error at some point
gap> IsTorsionFree(ExamplesOfSomePcpGroups(5));
true
#
gap> # Verify IsGeneratorsOfMagmaWithInverses warnings are silenced
gap> IsGeneratorsOfMagmaWithInverses(GeneratorsOfGroup(ExamplesOfSomePcpGroups(5)));
true
#
gap> # Check for a bug reported 2012-01-19 by Robert Morse
gap> g := PcGroupToPcpGroup(SmallGroup(48,1));
Pcp-group with orders [ 2, 2, 2, 2, 3 ]
gap> # The next two commands used to trigger errors
gap> NonAbelianTensorSquare(Centre(g));
Pcp-group with orders [ 8 ]
gap> NonAbelianExteriorSquare(Centre(g));
Pcp-group with orders [ ]
#
gap> # Check for a bug reported 2012-01-19 by Robert Morse
gap> F := FreeGroup("x","y");
<free group on the generators [ x, y ]>
gap> x := F.1;; y := F.2;;
gap> G := F/[x^2/y^24, y^24, y^x/y^23];
<fp group on the generators [ x, y ]>
gap> iso := IsomorphismPcGroup(G);
[ x, y ] -> [ f1, f2*f5 ]
gap> iso1 := IsomorphismPcpGroup(Image(iso));
[ f1, f2, f3, f4, f5 ] -> [ g1, g2, g3, g4, g5 ]
gap> G := Image(iso*iso1);
Pcp-group with orders [ 2, 2, 2, 2, 3 ]
gap> # The next command used to trigger an error
gap> NonAbelianTensorSquare(Image(iso*iso1));
Pcp-group with orders [ 2, 2, 3, 2, 2, 2, 2 ]
#
gap> # The problem with the previous example is/was that Igs(G)
gap> # is set to a non-standard value. Experiment with that some more
gap> G := Parent(G);; # does nothing in GAP >= 4.13 -- possibly due to https://github.com/gap-system/gap/pull/5631
gap> igs := [ G.1, G.2*G.5, G.3*G.4*G.5^2, G.4*G.5, G.5 ];;
gap> G := Subgroup(G, igs);;
gap> SetIgs(G, igs);
gap> Igs(G);
[ g1, g2*g5, g3*g4*g5^2, g4*g5, g5 ]
gap> # Unfortunately, it seems that a lot of code that
gap> # really should be using Ngs or Cgs is using Igs incorrectly.
gap> # For example, direct products could return *invalid* embeddings:
gap> D := DirectProduct(G, G);
Pcp-group with orders [ 2, 2, 2, 2, 3, 2, 2, 2, 2, 3 ]
gap> hom:=Embedding(D,1);;
gap> mapi:=MappingGeneratorsImages(hom);;
gap> GroupHomomorphismByImages(Source(hom),Range(hom),mapi[1],mapi[2]) <> fail;
true
gap> hom:=Projection(D,1);;
gap> mapi:=MappingGeneratorsImages(hom);;
gap> GroupHomomorphismByImages(Source(hom),Range(hom),mapi[1],mapi[2]) <> fail;
true
#
gap> # Check for bug computing Schur extension of infinite cyclic groups,
gap> # found by Max Horn 2012-05-25
gap> G:=AbelianPcpGroup(1,[0]);
Pcp-group with orders [ 0 ]
gap> # The next command used to trigger an error
gap> SchurExtension(G);
Pcp-group with orders [ 0 ]
#
gap> # Check for bug computing Schur extensions of subgroups, found by MH 2012-05-25.
gap> G:=HeisenbergPcpGroup(2);
Pcp-group with orders [ 0, 0, 0, 0, 0 ]
gap> H:=Subgroup(G,[G.2^3*G.3^2, G.1^9]);
Pcp-group with orders [ 0, 0, 0 ]
gap> # The next command used to trigger an error
gap> SchurExtension(H);
Pcp-group with orders [ 0, 0, 0, 0, 0, 0 ]
#
gap> # Check for bug computing Schur extensions of subgroups, found by MH 2012-05-25.
gap> G:=HeisenbergPcpGroup(2);
Pcp-group with orders [ 0, 0, 0, 0, 0 ]
gap> H:=Subgroup(G,[G.1, G.2]);
Pcp-group with orders [ 0, 0 ]
gap> # The next command used to trigger an error
gap> SchurExtension(H);
Pcp-group with orders [ 0, 0, 0 ]
#
gap> # Check for bug computing normalizer of two subgroups, found by MH 2012-05-30.
gap> # The problem was caused by incorrect resp. overly restrictive use of Parent().
gap> G:=HeisenbergPcpGroup(2);
Pcp-group with orders [ 0, 0, 0, 0, 0 ]
gap> A:=Subgroup(Subgroup(G,[G.2,G.3,G.4,G.5]), [G.3]);
Pcp-group with orders [ 0 ]
gap> B:=Subgroup(Subgroup(G,[G.1,G.4,G.5]), [G.4]);
Pcp-group with orders [ 0 ]
gap> Normalizer(A,B);
Pcp-group with orders [ 0 ]
gap> # The following used to trigger the error "arguments must have a common parent group"
gap> Normalizer(B,A);
Pcp-group with orders [ 0 ]
#
gap> # In polycyclic 2.9 and 2.10, the code for 2-cohomology computations was broken.
gap> G := UnitriangularPcpGroup(3,0);
Pcp-group with orders [ 0, 0, 0 ]
gap> mats := G!.mats;
[ [ [ 1, 1, 0 ], [ 0, 1, 0 ], [ 0, 0, 1 ] ],
[ [ 1, 0, 0 ], [ 0, 1, 1 ], [ 0, 0, 1 ] ],
[ [ 1, 0, 1 ], [ 0, 1, 0 ], [ 0, 0, 1 ] ] ]
gap> C := CRRecordByMats(G,mats);;
gap> cc := TwoCohomologyCR(C);;
gap> cc.factor.rels;
[ 2, 0, 0 ]
gap> c := cc.factor.prei[2];
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, -1, 1 ]
gap> cc.gcb;
[ [ 0, 0, 1, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
[ 0, 0, -1, 0, 0, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 0, 0, 0 ],
[ 0, -1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, -1 ],
[ -1, 0, 1, 1, 0, 0, 0, -1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0 ],
[ 0, -1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 1 ] ]
gap> cc.gcc;
[ [ 1, 0, 0, 0, 0, -2, -1, 0, 1, 1, -1, -1, 0, 0, 0, 0, 0, 0 ],
[ 0, 1, 0, 0, -1, -1, 0, 0, 1, 0, 0, -1, 0, 0, 0, 0, 0, 0 ],
[ 0, 0, 1, 0, 0, -2, 0, 0, 1, 0, 0, -1, 0, 0, 0, 0, 0, 0 ],
[ 0, 0, 0, 1, 0, 0, -1, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0 ],
[ 0, 0, 0, 0, 0, 1, 0, 0, -1, 0, 0, 1, 0, 0, 0, 0, 0, 0 ],
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, -1, 1 ],
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, -1 ] ]
#
gap> # LowerCentralSeriesOfGroup for non-nilpotent pcp-groups used to trigger
gap> # an infinite recursion
gap> G := PcGroupToPcpGroup(SmallGroup(6,1));
Pcp-group with orders [ 2, 3 ]
gap> LowerCentralSeriesOfGroup(G);
[ Pcp-group with orders [ 2, 3 ], Pcp-group with orders [ 3 ] ]
#
# Fix a bug computing NormalizerPcpGroup, see
# <https://github.com/gap-packages/polycyclic/issues/2>
#
gap> P2:=SylowSubgroup(GL(IsPermGroup,7,2),2);
<permutation group of size 2097152 with 21 generators>
gap> iso := IsomorphismPcpGroup(P2);;
gap> G:=Image(iso);;
gap> U := Subgroup(G,[G.3*G.5*G.8*G.9*G.10*G.13*G.15*G.17*G.18*G.19,G.15*G.17]);;
gap> N := NormalizerPcpGroup( G, U );;
gap> Images(iso, Normalizer( P2, PreImagesNC(iso, U) )) = N;
true
#
# Fix a bug computing ComplementClassesCR, see
# <https://github.com/gap-packages/polycyclic/issues/3>
#
gap> G:=PcGroupToPcpGroup(PcGroupCode(37830811398924985638637008775811, 144));
Pcp-group with orders [ 2, 2, 2, 2, 3, 3 ]
gap> classes := FiniteSubgroupClasses(G);;
gap> Length(classes);
86
gap> Collected(List(classes, c -> Size(Representative(c))));
[ [ 1, 1 ], [ 2, 7 ], [ 3, 2 ], [ 4, 11 ], [ 6, 14 ], [ 8, 7 ], [ 9, 1 ],
[ 12, 14 ], [ 16, 1 ], [ 18, 7 ], [ 24, 2 ], [ 36, 11 ], [ 72, 7 ],
[ 144, 1 ] ]
#
# bug in StabilizerIntegralAction
# <https://github.com/gap-packages/polycyclic/issues/15>
#
gap> P:=PolynomialRing(Integers);; x:=P.1;;
gap> G:=MaximalOrderByUnitsPcpGroup(x^4+x^3+x^2+x+1);
Pcp-group with orders [ 10, 0, 0, 0, 0, 0 ]
gap> pcps := PcpsOfEfaSeries(G);
[ Pcp [ g1 ] with orders [ 2 ], Pcp [ g1^2 ] with orders [ 5 ],
Pcp [ g2 ] with orders [ 0 ], Pcp [ g3, g4, g5, g6 ] with orders
[ 0, 0, 0, 0 ] ]
gap> mats := AffineActionByElement( Pcp(G), pcps[4], G.2 );;
gap> e := [ 0, 0, 0, 0, 1 ];
[ 0, 0, 0, 0, 1 ]
gap> stab := StabilizerIntegralAction( G, mats, e );
Pcp-group with orders [ 10, 0 ]
gap> CheckStabilizer(G, stab, mats, e);
#I Stabilizer not increasing: exiting.
true
#
# bug in AddToIgs: in infinite pcp groups, we must also take inverses of
# generators into account.
# <https://github.com/gap-packages/polycyclic/issues/16>
#
gap> ftl := FromTheLeftCollector( 26 );;
gap> SetRelativeOrder( ftl, 1, 5 );
gap> SetPower( ftl, 1, [ 2, 1, 3, 1, 4, 1, 5, 1, 6, 1 ] );
gap> SetRelativeOrder( ftl, 2, 5 );
gap> SetPower( ftl, 2, [] );
gap> SetRelativeOrder( ftl, 3, 5 );
gap> SetPower( ftl, 3, [] );
gap> SetRelativeOrder( ftl, 4, 5 );
gap> SetPower( ftl, 4, [] );
gap> SetRelativeOrder( ftl, 5, 5 );
gap> SetPower( ftl, 5, [] );
gap> SetRelativeOrder( ftl, 6, 5 );
gap> SetPower( ftl, 6, [] );
gap> SetConjugate( ftl, 2, 1, [ 6, 1 ] );
gap> SetConjugate( ftl, 3, 1, [ 2, 1 ] );
gap> SetConjugate( ftl, 4, 1, [ 3, 1 ] );
gap> SetConjugate( ftl, 5, 1, [ 4, 1 ] );
gap> SetConjugate( ftl, 6, 1, [ 5, 1 ] );
gap> SetConjugate( ftl, 7, 1, [ 26, -1 ] );
gap> SetConjugate( ftl, 7, 6, [ 22, -1 ] );
gap> SetConjugate( ftl, 8, 1, [ 7, 1 ] );
gap> SetConjugate( ftl, 8, 2, [ 23, -1 ] );
gap> SetConjugate( ftl, 9, 1, [ 8, 1 ] );
gap> SetConjugate( ftl, 9, 3, [ 24, -1 ] );
gap> SetConjugate( ftl, 10, 1, [ 9, 1 ] );
gap> SetConjugate( ftl, 10, 4, [ 25, -1 ] );
gap> SetConjugate( ftl, 11, 1, [ 10, 1 ] );
gap> SetConjugate( ftl, 11, 5, [ 26, -1 ] );
gap> SetConjugate( ftl, 12, 1, [ 11, 1, 26, -1 ] );
gap> SetConjugate( ftl, 12, 6, [ 7, 1, 22, -1 ] );
gap> SetConjugate( ftl, 13, 1, [ 12, 1 ] );
gap> SetConjugate( ftl, 13, 2, [ 8, 1, 23, -1 ] );
gap> SetConjugate( ftl, 14, 1, [ 13, 1 ] );
gap> SetConjugate( ftl, 14, 3, [ 9, 1, 24, -1 ] );
gap> SetConjugate( ftl, 15, 1, [ 14, 1 ] );
gap> SetConjugate( ftl, 15, 4, [ 10, 1, 25, -1 ] );
gap> SetConjugate( ftl, 16, 1, [ 15, 1 ] );
gap> SetConjugate( ftl, 16, 5, [ 11, 1, 26, -1 ] );
gap> SetConjugate( ftl, 17, 1, [ 16, 1, 26, -1 ] );
gap> SetConjugate( ftl, 17, 6, [ 12, 1, 22, -1 ] );
gap> SetConjugate( ftl, 18, 1, [ 17, 1 ] );
gap> SetConjugate( ftl, 18, 2, [ 13, 1, 23, -1 ] );
gap> SetConjugate( ftl, 19, 1, [ 18, 1 ] );
gap> SetConjugate( ftl, 19, 3, [ 14, 1, 24, -1 ] );
gap> SetConjugate( ftl, 20, 1, [ 19, 1 ] );
gap> SetConjugate( ftl, 20, 4, [ 15, 1, 25, -1 ] );
gap> SetConjugate( ftl, 21, 1, [ 20, 1 ] );
gap> SetConjugate( ftl, 21, 5, [ 16, 1, 26, -1 ] );
gap> SetConjugate( ftl, 22, 1, [ 21, 1, 26, -1 ] );
gap> SetConjugate( ftl, 22, 6, [ 17, 1, 22, -1 ] );
gap> SetConjugate( ftl, 23, 1, [ 22, 1 ] );
gap> SetConjugate( ftl, 23, 2, [ 18, 1, 23, -1 ] );
gap> SetConjugate( ftl, 24, 1, [ 23, 1 ] );
gap> SetConjugate( ftl, 24, 3, [ 19, 1, 24, -1 ] );
gap> SetConjugate( ftl, 25, 1, [ 24, 1 ] );
gap> SetConjugate( ftl, 25, 4, [ 20, 1, 25, -1 ] );
gap> SetConjugate( ftl, 26, 1, [ 25, 1 ] );
gap> SetConjugate( ftl, 26, 5, [ 21, 1, 26, -1 ] );
gap> SetConjugate( ftl, -7, 1, [ 26, 1 ] );
gap> SetConjugate( ftl, -7, 6, [ 22, 1 ] );
gap> SetConjugate( ftl, -8, 1, [ 7, -1 ] );
gap> SetConjugate( ftl, -8, 2, [ 23, 1 ] );
gap> SetConjugate( ftl, -9, 1, [ 8, -1 ] );
gap> SetConjugate( ftl, -9, 3, [ 24, 1 ] );
gap> SetConjugate( ftl, -10, 1, [ 9, -1 ] );
gap> SetConjugate( ftl, -10, 4, [ 25, 1 ] );
gap> SetConjugate( ftl, -11, 1, [ 10, -1 ] );
gap> SetConjugate( ftl, -11, 5, [ 26, 1 ] );
gap> SetConjugate( ftl, -12, 1, [ 11, -1, 26, 1 ] );
gap> SetConjugate( ftl, -12, 6, [ 7, -1, 22, 1 ] );
gap> SetConjugate( ftl, -13, 1, [ 12, -1 ] );
gap> SetConjugate( ftl, -13, 2, [ 8, -1, 23, 1 ] );
gap> SetConjugate( ftl, -14, 1, [ 13, -1 ] );
gap> SetConjugate( ftl, -14, 3, [ 9, -1, 24, 1 ] );
gap> SetConjugate( ftl, -15, 1, [ 14, -1 ] );
gap> SetConjugate( ftl, -15, 4, [ 10, -1, 25, 1 ] );
gap> SetConjugate( ftl, -16, 1, [ 15, -1 ] );
gap> SetConjugate( ftl, -16, 5, [ 11, -1, 26, 1 ] );
gap> SetConjugate( ftl, -17, 1, [ 16, -1, 26, 1 ] );
gap> SetConjugate( ftl, -17, 6, [ 12, -1, 22, 1 ] );
gap> SetConjugate( ftl, -18, 1, [ 17, -1 ] );
gap> SetConjugate( ftl, -18, 2, [ 13, -1, 23, 1 ] );
gap> SetConjugate( ftl, -19, 1, [ 18, -1 ] );
gap> SetConjugate( ftl, -19, 3, [ 14, -1, 24, 1 ] );
gap> SetConjugate( ftl, -20, 1, [ 19, -1 ] );
gap> SetConjugate( ftl, -20, 4, [ 15, -1, 25, 1 ] );
gap> SetConjugate( ftl, -21, 1, [ 20, -1 ] );
gap> SetConjugate( ftl, -21, 5, [ 16, -1, 26, 1 ] );
gap> SetConjugate( ftl, -22, 1, [ 21, -1, 26, 1 ] );
gap> SetConjugate( ftl, -22, 6, [ 17, -1, 22, 1 ] );
gap> SetConjugate( ftl, -23, 1, [ 22, -1 ] );
gap> SetConjugate( ftl, -23, 2, [ 18, -1, 23, 1 ] );
gap> SetConjugate( ftl, -24, 1, [ 23, -1 ] );
gap> SetConjugate( ftl, -24, 3, [ 19, -1, 24, 1 ] );
gap> SetConjugate( ftl, -25, 1, [ 24, -1 ] );
gap> SetConjugate( ftl, -25, 4, [ 20, -1, 25, 1 ] );
gap> SetConjugate( ftl, -26, 1, [ 25, -1 ] );
gap> SetConjugate( ftl, -26, 5, [ 21, -1, 26, 1 ] );
gap>
gap> G := PcpGroupByCollector(ftl);
Pcp-group with orders [ 5, 5, 5, 5, 5, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0 ]
gap> a := G.1;;
gap> b := G.1^4*G.2^4*G.3^4*G.4^4*G.5^4*G.6^3*G.7;;
gap> c := G.1^4*G.2^4*G.3^4*G.4^4*G.5^4*G.6^4*G.7;;
gap> H := Subgroup(G,[a,b,c]);
Pcp-group with orders [ 5, 5, 5, 5, 5, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0 ]
gap> G.1 in H;
true
gap> G.26 in H;
true
gap> G.1*G.26 in H;
true
gap> G = H;
true
#
# bug in IsConjugate: it should return a boolean, but instead of 'true' it
# returned a conjugating element.
# <https://github.com/gap-packages/polycyclic/issues/18>
#
gap> H := DihedralPcpGroup( 0 );
Pcp-group with orders [ 2, 0 ]
gap> IsConjugate(H,One(H),One(H));
true
gap> IsConjugate(H,H.1, H.2);
false
gap> IsConjugate(H,H.1, H.1^Random(H));
true
gap> DihedralPcpGroup( 2 );; # used to run into an error
#
# bug in OrbitIntegralAction
# <https://github.com/gap-packages/polycyclic/issues/21>
#
gap> G:=ExamplesOfSomePcpGroups(8);
Pcp-group with orders [ 0, 0, 0, 0, 0 ]
gap> mats:=RepresentationForPcpCollector(Collector(G));;
gap> e:=[8,-4,5,2,13,-17,9];;
gap> f := e * MappedVector( [ -2, 2, 0, 5, 5 ], mats );
[ 8, -4, 19, 34, 51, -17, 5 ]
gap> o := OrbitIntegralAction( G, mats, e, f );
rec( prei := g1^-90*g2^2*g3^-44*g4^16*g5^16,
stab := Pcp-group with orders [ 0 ] )
gap> CheckOrbit(G, o.prei, mats, e, f);
true
gap> CheckStabilizer(G, o.stab, mats, e);
#I Orbit longer than limit: exiting.
true
#
# Fix a bug in OneCoboundariesCR which lead to an error in OneCohomologyCR.
# <https://github.com/gap-packages/polycyclic/issues/25>
#
gap> G:=HeisenbergPcpGroup(1);
Pcp-group with orders [ 0, 0, 0 ]
gap> N:=Center(G);
Pcp-group with orders [ 0 ]
gap> C:=CRRecordBySubgroup(G,N);;
gap> OneCoboundariesCR(C);
[ ]
gap> OneCohomologyCR(C);
rec(
factor := rec( denom := [ ], gens := [ [ 1, 0 ], [ 0, 1 ] ],
imgs := [ [ 1, 0 ], [ 0, 1 ] ], prei := [ [ 1, 0 ], [ 0, 1 ] ],
rels := [ 0, 0 ] ), gcb := [ ], gcc := [ [ 1, 0 ], [ 0, 1 ] ] )
#
# Test for a regression in TorsionSubgroup (reported by Sam Tertooy)
#
gap> TorsionSubgroup(AbelianPcpGroup([4,3]));
Pcp-group with orders [ 4, 3 ]
#
# Fix a bug in NormalClosureOp which resulted in a non-abelian group
# being in the IsAbelian (and even the IsCyclic) filter.
# <https://github.com/gap-packages/polycyclic/issues/28>
#
gap> G:=PcGroupToPcpGroup(SmallGroup(5^6,500));
Pcp-group with orders [ 5, 5, 5, 5, 5, 5 ]
gap> N:=NormalClosure(Group(G.2), Group(G.3));
Pcp-group with orders [ 5, 5, 5, 5 ]
gap> IsCyclic(N);
false
gap> IsAbelian(N);
false
gap> PrintPcpPresentation(N);
g1^5 = id
g2^5 = id
g3^5 = id
g4^5 = id
g2 ^ g1 = g2 * g4
#
# Fix a bug in Intersection where relative orders were not properly taken into
# account, which lead to a too small result.
# <https://github.com/gap-packages/polycyclic/issues/33>
#
gap> free := FreeGroup(4);;
gap> AssignGeneratorVariables(free);
#I Assigned the global variables [ f1, f2, f3, f4 ]
gap> q := free / [ f1^2*f3^-1*f2^-2,
> f1^-1*f2*f1*f3^-1*f2^-1,
> f3^2,
> f1^-1*f3*f1*f4^-1*f3^-1,
> f2^-1*f3*f2*f4^-1*f3^-1,
> f2*f3*f2^-1*f4^-1*f3^-1,
> f4^2,
> f1^-1*f4*f1*f4^-1,
> f2^-1*f4*f2*f4^-1,
> f2*f4*f2^-1*f4^-1,
> f3^-1*f4*f3*f4^-1 ];;
gap> pcpq := PcpGroupFpGroupPcPres(q);
Pcp-group with orders [ 2, 0, 2, 2 ]
gap> AssignGeneratorVariables(pcpq);
#I Assigned the global variables [ g1, g2, g3, g4 ]
gap> sub := Subgroup(pcpq, [pcpq.2, pcpq.4]);
Pcp-group with orders [ 0, 2 ]
gap> sub2 := sub^pcpq.1;
Pcp-group with orders [ 0, 2 ]
gap> Pcp(Intersection(sub, sub2));
Pcp [ g2^2, g4 ] with orders [ 0, 2 ]
#
# For trivial homomorphisms, only the identity has a preimage!
# <https://github.com/gap-packages/polycyclic/issues/39>
#
gap> G := AbelianPcpGroup( [ 2 ] );
Pcp-group with orders [ 2 ]
gap> phi := GroupHomomorphismByImages( G, G, [ G.1 ], [ Identity( G ) ] );
[ g1 ] -> [ id ]
gap> PreImagesRepresentativeNC( phi, One(G) );
id
gap> PreImagesRepresentativeNC( phi, G.1 );
fail
#
gap> G := AbelianPcpGroup( [ 2, 2 ] );
Pcp-group with orders [ 2, 2 ]
gap> phi := GroupHomomorphismByImages( G, G, [ G.1, G.2 ], [ Identity( G ), G.2 ] );
[ g1, g2 ] -> [ id, g2 ]
gap> PreImagesRepresentativeNC( phi, One(G) );
id
gap> PreImagesRepresentativeNC( phi, G.2 );
g2
gap> PreImagesRepresentativeNC( phi, G.1 );
fail
#
# Fix a bug in AddToIgs causing wrong results for abelian groups
# <https://github.com/gap-packages/polycyclic/issues/38>
# <https://github.com/gap-packages/polycyclic/issues/40>
#
gap> g := AbelianPcpGroup(3);;
gap> h := Subgroup(g, [ g.1, g.1^-1*g.2, g.2^2*g.3 ]);;
gap> Index(g,h);
1
gap> g=h;
true
gap> H := ExamplesOfSomePcpGroups( 15 );;
gap> G := H/LowerCentralSeriesOfGroup( H )[8];;
gap> g := (G.2^-2*G.3^3*G.5^2*G.8^-6*G.9^45*G.10^-24);;
gap> srcs := [ G.2*G.5^-1, G.3, G.6, G.7, G.8, G.9, G.10 ];;
gap> M := Subgroup( G, srcs );;
gap> N := LowerCentralSeriesOfGroup( G )[7];;
gap> idG := Identity( G );;
gap> imgs := [ G.9^-3*G.10^-3, G.9^-2, G.9^4, G.10^-2, idG, idG, idG ];;
gap> diff := GroupHomomorphismByImages( M, N, srcs, imgs);;
gap> Ker := Kernel( diff );;
gap> g in Ker;
true
gap> HirschLength( Ker );
5
#
# Fix a bug in NormalizerOfComplement
# <https://github.com/gap-packages/polycyclic/issues/45>
# <https://github.com/gap-packages/polycyclic/issues/88>
#
gap> C := AbelianPcpGroup( [ 2, 3 ] );;
gap> H := Subgroup( C, [ C.1 ] );;
gap> N := Subgroup( C, [ C.2 ] );;
gap> I := NormalIntersection( N, H );;
gap> NormalizerOfComplement( C, H, N, I );
Pcp-group with orders [ 2, 3 ]
# second test case for issue #45 / #88
gap> G:= AbelianPcpGroup( 2, [ 2, 3 ] );;
gap> Length( ConjugacyClassesSubgroups( G ) ) = 4;
true
#
# Fix a bug in IsNormal
# <https://github.com/gap-packages/polycyclic/issues/46>
#
gap> g := PcGroupToPcpGroup(SmallGroup(48,1));
Pcp-group with orders [ 2, 2, 2, 2, 3 ]
gap> S := SylowSubgroup( g, 2 );
Pcp-group with orders [ 2, 2, 2, 2 ]
gap> T := S^g.5;
Pcp-group with orders [ 2, 2, 2, 2 ]
gap> IsNormal( S, T );
false
gap> IsNormal( T, S );
false
#
# PreImages resp. PreImagesSet used to run into a "method not found"
# error when the input set is not contained in the image of the map.
# <https://github.com/gap-packages/polycyclic/issues/47>
#
gap> G := AbelianPcpGroup([0]);
Pcp-group with orders [ 0 ]
gap> phi := GroupHomomorphismByImages(G,G,[G.1],[One(G)]);
[ g1 ] -> [ id ]
gap> H := PreImagesSet(phi, G);
Pcp-group with orders [ 0 ]
gap> G = H;
true
#
# TorsionSubgroup returned a wrong results for abelian groups
# (was not in a released version)
# <https://github.com/gap-packages/polycyclic/issues/52>
#
gap> TorsionSubgroup(AbelianPcpGroup([3,2,0,0]));
Pcp-group with orders [ 3, 2 ]
gap> TorsionSubgroup(AbelianPcpGroup([2,3,0,0]));
Pcp-group with orders [ 2, 3 ]
#
# Wrong result for intersection of subgroups of an abelian group
# (was not in a released version)
# <https://github.com/gap-packages/polycyclic/issues/53>
#
gap> G := AbelianPcpGroup([4,2]);;
gap> M := Group(G.1);;
gap> N := Group(G.1*G.2);;
gap> G.1^2 in N;
true
gap> G.1^2 in M;
true
gap> G.1^2 in Intersection(N,M);
true
#
# Fix a bug in ConjugacyElementsBySeries
# <https://github.com/gap-packages/polycyclic/issues/58>
#
gap> G := ExamplesOfSomePcpGroups( 10 );;
gap> g := G.1;;
gap> h := g^(G.2*G.3);;
gap> k := ConjugacyElementsBySeries( G, g, h, PcpsOfEfaSeries( G ) );;
gap> g^k = h;
true
#
# Fix a bug causing Random to fail for the trivial group
# <https://github.com/gap-packages/polycyclic/issues/59>
#
gap> Random( TrivialGroup( IsPcpGroup ) );
id
#
# Allow Centralizer to fall back on generic GAP methods
# <https://github.com/gap-packages/polycyclic/issues/64>
#
gap> G := PcGroupToPcpGroup( SmallGroup( 16, 11 ) );;
gap> g := G.1*G.3*G.4;;
gap> H := Subgroup( G,[ G.2, G.3, G.4 ] );;
gap> Centralizer( H, g );
Pcp-group with orders [ 2, 2 ]
#
# Fix a bug in CentralizerBySeries
# <https://github.com/gap-packages/polycyclic/issues/65>
#
gap> G := PcGroupToPcpGroup( SmallGroup( 16, 11 ) );;
gap> g := G.2*G.3*G.4;;
gap> cc := ConjugacyClass( G, g );;
gap> C := Centralizer( cc );
Pcp-group with orders [ 2, 2, 2 ]
gap> Igs( C );
[ g2, g3, g4 ]
#
# Fix bug with IsSingleValued / CoKernelOfMultiplicativeGeneralMapping
# for certain trivial maps, which used to raise an error in the example
# below, because MappedVector was called with an empty list of generators.
#
gap> G:=TrivialGroup(IsPcpGroup);;
gap> H:=AbelianGroup(IsPcpGroup,[0]);;
gap> GroupHomomorphismByImages(G, H, [One(G)], [One(H)]);
[ id ] -> [ id ]
#
# Fix a bug in the AbelianGroupCons method for IsPcpGroup.
# (Generators of order 1 are in principle supported,
# but we got an error when all generators had order 1,
# and the group was corrupted when some but not all generators had order 1.)
#
gap> AbelianGroup( IsPcpGroup, [ 1 ] );
Pcp-group with orders [ ]
gap> g:= AbelianGroup( IsPcpGroup, [ 1, 2 ] );
Pcp-group with orders [ 2 ]
gap> List( GeneratorsOfGroup( g ), Order );
[ 1, 2 ]
gap> AbelianPcpGroup( 1 );
Pcp-group with orders [ 0 ]
gap> AbelianPcpGroup( [ 1 ] );
Pcp-group with orders [ ]
gap> AbelianPcpGroup( 1, [ 1 ] );
Pcp-group with orders [ ]
gap> AbelianPcpGroup( 2 );
Pcp-group with orders [ 0, 0 ]
gap> AbelianPcpGroup( [ 2, 3 ] );
Pcp-group with orders [ 2, 3 ]
gap> AbelianPcpGroup( 2, [ 2, 3 ] );
Pcp-group with orders [ 2, 3 ]
gap> AbelianPcpGroup( 2, [ 2, 3, 4 ] );
Pcp-group with orders [ 2, 3 ]
gap> AbelianPcpGroup( 2, [ 2 ] );
Pcp-group with orders [ 2, 0 ]
#
# Fix bug in FrattiniSubgroup
# Reported by Heiko Dietrich (2024-02-19)
#
gap> G:=PcGroupToPcpGroup(SmallGroup(11025,6));;
gap> F:=FrattiniSubgroup(G);;
gap> Size(F); # used to produce a group of order 49
21
#
# Fixed a bug in IsConjugate for a finite pcp-group
# <https://github.com/gap-packages/polycyclic/issues/70>
#
gap> G := PcGroupToPcpGroup( SmallGroup( 1600, 10260 ) );;
gap> G := Subgroup( G, [ G.1, G.2, G.3, G.4 ] );;
gap> g := G.2*G.4;; h := g^(G.1*G.3);;
gap> IsConjugate( G, g, h );
true
#
# Fixed a bug in stabilizer integral action
# <https://github.com/gap-packages/polycyclic/issues/71>
#
gap> G := ExamplesOfSomePcpGroups( 10 );;
gap> g := G.1^2*G.3^3*G.4^-3;;
gap> h := g^(G.1*G.2^2);;
gap> pcps := PcpsOfEfaSeries( G );;
gap> k := ConjugacyElementsBySeries( G, g, h, pcps );
g1*g2^2
gap> g^k = h;
true
#
# Fixed a bug in OrbitIntegralAction
# This fix bug has a temporary solution by commenting the code in
# gap/action/orbstab.gi lines 592-594
#
gap> ftl := FromTheLeftCollector( 2 );;
gap> SetRelativeOrder( ftl, 2, 2 );
gap> G := PcpGroupByCollector( ftl );;
gap> A := [ [ 1, 1, 0, 0], [ 0, 1, 0 , 0], [ 0, 0, 1, 0], [ 0, 0, 0, 1] ];;
gap> B := DiagonalMat( [-1, -1, -1, -1] );;
gap> OrbitIntegralAction( G, [A,B], [1,0,0,0], [-1,0,0,0] );
rec( prei := g2, stab := Pcp-group with orders [ ] )
#
# Fix a bug in SchurCovers
# <https://github.com/gap-packages/polycyclic/issues/93>
#
gap> SchurCovers( CyclicGroup( 4 ) );
[ <pc group of size 4 with 2 generators> ]
#
gap> STOP_TEST( "bugfix.tst" );
[ Dauer der Verarbeitung: 0.7 Sekunden
(vorverarbeitet)
]
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2026-03-28
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