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MATRIX GROUPS

 
Introduction
      Introduction to Matrix Groups
      The Support
      The Category of Matrix Groups
      The Construction of a Matrix Group
 
Creation of a Matrix Group
      Construction of the General Linear Group
      Construction of a Matrix Group Element
      Construction of a General Matrix Group
      Changing Rings
      Coercion between Matrix Structures
 
Basic Invariants of a Matrix Group
      Accessing a Group
      Group Order
      Abstract Group Predicates
 
Homomorphisms
 
Standard Matrix Groups
      Chevalley Groups
      Classical Groups
            General and Special Linear Groups
            General and Special Unitary Groups
            Symplectic Groups
            Orthogonal Groups
            Suzuki Groups
      Construction of Extensions
 
Operations on Matrices
      Arithmetic with Matrices
      Predicates for Matrices
      Matrix Invariants
      Membership and Equality
      Set Operations
 
Conjugacy
 
Subgroups
      Construction of Subgroups
      Elementary Properties of Subgroups
      Standard Subgroups
      Low Index Subgroups
 
Quotient Groups
      Construction of Quotient Groups
      Abelian, Nilpotent and Soluble Quotients
 
Matrix Group Actions
      Orbits and Stabilizers
      Orbit and Stabilizer Functions for Large Groups
      Action on Orbits
      Action on a Coset Space
      Action on the Natural G-Module
 
Normal and Subnormal Subgroups
      Characteristic Subgroups and Subgroup Series
      The Soluble Radical and its Quotient
      Composition and Chief Factors
 
Coset Tables and Transversals
 
Presentations
      Generators and Relations
      Matrices as Words
 
Representation Theory
 
Base and Strong Generating Set
      Introduction
      Controlling Selection of a Base
      Construction of a Base and Strong Generating Set
      Defining Values for Attributes
      Accessing the Base and Strong Generating Set
 
Soluble Matrix Groups
      Conversion to a PC-Group
      Soluble Group Functions
      p-group Functions
      Abelian Group Functions
 
Matrix Groups of Large Degree
      Introduction
      Classical forms
      Recognizing Classical Groups in their Natural Representation
      Primitivity Testing
      Semilinearity
      Tensor Products
      Tensor-induced Groups
      Decompositions with Respect to a Normal Subgroup
            Accessing the Decomposition Information
      Writing Representations over Subfields
      Related Functions
 
Bibliography







DETAILS

 
Introduction

      Introduction to Matrix Groups

      The Support

      The Category of Matrix Groups

      The Construction of a Matrix Group

 
Creation of a Matrix Group

      Construction of the General Linear Group
            GeneralLinearGroup(n, R) : RngIntElt, Rng -> GrpMat
            Example GrpMat_Create (H21E1)

      Construction of a Matrix Group Element
            elt< G | L > : GrpMat, List(RngElt) -> GrpMatElt
            G ! Q : GrpMat, [ RngElt ] -> GrpMatElt
            ElementToSequence(g) : GrpMatElt -> [ RngElt ]
            Identity(G) : GrpMat -> GrpMatElt
            Example GrpMat_Matrices (H21E2)

      Construction of a General Matrix Group
            MatrixGroup< n, R | L > : RngIntElt, Rng, List -> GrpMat
            Example GrpMat_Constructor (H21E3)
            Example GrpMat_GLSylow (H21E4)

      Changing Rings
            ChangeRing(G, S) : GrpMat, Rng -> GrpMat, Map
            ChangeRing(G, S, f) : GrpMat, Rng, Map -> GrpMat, Map
            RestrictField(G, S) : GrpMat, FldFin -> GrpMat, Map
            ExtendField(G, L) : GrpMat, FldFin -> GrpMat, Map

      Coercion between Matrix Structures
            R ! g : AlgMat, GrpMatElt -> RngMatElt
            G ! r : GrpMat, RngMatElt -> GrpMatElt
            M ! g : ModMat, GrpMatElt -> ModMatElt
            G ! m : GrpMat, ModMatElt -> GrpMatElt

 
Basic Invariants of a Matrix Group

      Accessing a Group
            G . i : GrpMat, RngIntElt -> GrpMatElt
            Degree(G) : GrpMat -> RngIntElt
            Generators(G) : GrpMat -> { GrpMatElt }
            NumberOfGenerators(G) : GrpMat -> RngIntElt
            CoefficientRing(G) : GrpMat -> Rng
            RSpace(G) : GrpMat -> ModTupRng
            VectorSpace(G) : GrpMat -> ModTupFld
            GModule(G) : GrpMat -> ModGrp
            Generic(G) : GrpMat -> GrpMat
            Parent(G) : GrpMatElt -> GrpMat

      Group Order
            IsFinite(G) : GrpMat -> Bool, RngIntElt
            Order(G) : GrpMat -> RngIntElt
            FactoredOrder(G) : GrpMat -> [ <RngIntElt, RngIntElt> ]
            Example GrpMat_Order (H21E5)

      Abstract Group Predicates
            IsAbelian(G) : GrpMat -> BoolElt
            IsCyclic(G) : GrpMat -> BoolElt
            IsElementaryAbelian(G) : GrpMat -> BoolElt
            IsNilpotent(G) : GrpMat -> BoolElt
            IsSoluble(G) : GrpMat -> BoolElt
            IsPerfect(G) : GrpMat -> BoolElt
            IsSimple(G) : GrpMat -> BoolElt
            Example GrpMat_Order (H21E6)

 
Homomorphisms
      hom<G | L> : GrpMat, List -> Map
      Domain(f) : Map -> Grp
      Codomain(f) : Map -> Grp
      Image(f) : Map -> Grp
      Kernel(f) : Map -> Grp
      IsHomomorphism(G, H, Q) : GrpMat, GrpMat, SeqEnum[GrpMatElt] -> Bool, Map
      Example GrpMat_Homomorphism (H21E7)

 
Standard Matrix Groups

      Chevalley Groups
            ChevalleyGroup(s, n, K: parameters) : MonStgElt, RngIntElt, FldFin -> GrpMat

      Classical Groups

            General and Special Linear Groups
                  GeneralLinearGroup(arguments)
                  AffineGeneralLinearGroup(arguments)
                  SpecialLinearGroup(arguments)
                  AffineSpecialLinearGroup(arguments)

            General and Special Unitary Groups
                  GeneralUnitaryGroup(arguments)
                  SpecialUnitaryGroup(arguments)

            Symplectic Groups
                  SymplecticGroup(arguments)

            Orthogonal Groups
                  GeneralOrthogonalGroup(arguments)
                  GeneralOrthogonalGroupPlus(arguments)
                  GeneralOrthogonalGroupMinus(arguments)
                  SpecialOrthogonalGroup(arguments)
                  SpecialOrthogonalGroupPlus(arguments)
                  SpecialOrthogonalGroupMinus(arguments)
                  Omega(arguments)
                  OmegaPlus(arguments)
                  OmegaMinus(arguments)

            Suzuki Groups
                  SuzukiGroup(arguments)
                  Example GrpMat_Symplectic (H21E8)
                  Example GrpMat_Suzuki (H21E9)

      Construction of Extensions
            DirectProduct(G, H) : GrpMat, GrpMat -> GrpMat
            DirectProduct(Q) : [ GrpMat ] -> GrpMat
            SemiLinearGroup(G, S) : GrpMat, FldFin -> GrpMat
            TensorWreathProduct(G, H) : GrpMat, GrpPerm -> GrpMat
            WreathProduct(G, H) : GrpMat, GrpPerm -> GrpMat
            Example GrpMat_Constructions (H21E10)

 
Operations on Matrices

      Arithmetic with Matrices
            g * h : GrpMatElt, GrpMatElt -> GrpMatElt
            g ^ n : GrpMatElt, RngIntElt -> GrpMatElt
            g / h : GrpMatElt, GrpMatElt -> GrpMatElt
            g ^ h : GrpMatElt, GrpMatElt -> GrpMatElt
            (g, h) : GrpMatElt, GrpMatElt -> GrpMatElt
            (g_1, ..., g_r) : GrpMatElt, ..., GrpMatElt -> GrpMatElt
            Example GrpMat_Arithmetic (H21E11)

      Predicates for Matrices
            g eq h : GrpMatElt, GrpMatElt -> BoolElt
            g ne h : GrpMatElt, GrpMatElt -> BoolElt
            IsIdentity(g) : GrpMatElt -> BoolElt
            IsScalar(g) : GrpMatElt -> BoolElt

      Matrix Invariants
            Degree(g) : GrpMatElt -> RngIntElt
            HasFiniteOrder(g) : GrpMatElt -> BoolElt, RngIntElt
            Order(g) : GrpMatElt -> RngIntElt
            FactoredOrder(g) : GrpMatElt -> [ <RngIntElt, RngIntElt> ]
            Determinant(g) : GrpMatElt -> RngElt
            Trace(g) : GrpMatElt -> RngElt
            CharacteristicPolynomial(g: parameters) : GrpMatElt -> RngPolElt
            MinimalPolynomial(g) : GrpMatElt -> RngPolElt
            Example GrpMat_Invariants (H21E12)

      Membership and Equality
            g in G : GrpMatElt, GrpMat -> BoolElt
            g notin G : GrpMatElt, GrpMat -> BoolElt
            S subset G : { GrpMatElt }, GrpMat -> BoolElt
            H subset G : GrpMat, GrpMat -> BoolElt
            S notsubset G : { GrpMatElt }, GrpMat -> BoolElt
            H notsubset G : GrpMat, GrpMat -> BoolElt
            H eq G : GrpMat, GrpMat -> BoolElt
            H ne G : GrpMat, GrpMat -> BoolElt

      Set Operations
            NumberingMap(G) : GrpMat -> Map
            RandomProcess(G) : GrpMat -> Process
            Random(G: parameters) : GrpMat -> GrpMatElt
            Random(P) : Process -> GrpMatElt
            Example GrpMat_Random (H21E13)

 
Conjugacy
      Class(H, x) : GrpMat, GrpMatElt -> { GrpMatElt }
      ClassMap(G) : GrpMat -> Map
      ConjugacyClasses(G: parameters) : GrpMat -> [ < RngIntElt, RngIntElt, GrpMatElt > ]
      ClassRepresentative(G, x) : GrpMat, GrpMatElt -> GrpMatElt
      IsConjugate(G, g, h) : GrpMat, GrpMatElt, GrpMatElt -> BoolElt, GrpMatElt | Unass
      [Future release] IsConjugate(G, H, K) : GrpMat, GrpMat, GrpMat -> BoolElt, GrpMatElt | Unass
      Exponent(G) : GrpMat -> RngIntElt
      NumberOfClasses(G) : GrpMat -> RngIntElt
      PowerMap(G) : GrpMat -> Map
      AssertAttribute(G, "Classes", Q) : GrpMat, MonStgElt, [ GrpMatElt ] ->
      Example GrpMat_RationalMatrixGroupDatabase (H21E14)

 
Subgroups

      Construction of Subgroups
            sub<G | L> : GrpMat, List -> GrpMat
            ncl<G | L> : GrpMat, List -> GrpMat
            Example GrpMat_Subgroups (H21E15)

      Elementary Properties of Subgroups
            Index(G, H) : GrpMat, GrpMat -> RngIntElt
            FactoredIndex(G, H) : GrpMat, GrpMat -> [ <RngIntElt, RngIntElt> ]
            IsCentral(G, H) : GrpMat -> BoolElt
            IsMaximal(G, H) : GrpMat, GrpMat -> BoolElt
            IsNormal(G, H) : GrpMat, GrpMat -> BoolElt
            IsSubnormal(G, H) : GrpMat, GrpMat -> BoolElt

      Standard Subgroups
            H ^ g : GrpMat, GrpMatElt -> GrpMat
            H meet K : GrpMat, GrpMat -> GrpMat
            CommutatorSubgroup(G, H, K) : GrpMat, GrpMat, GrpMat -> GrpMat
            Centralizer(G, g) : GrpMat, GrpMatElt -> GrpMat
            Centralizer(G, H) : GrpMat, GrpMat -> GrpMat
            Core(G, H) : GrpMat, GrpMat -> GrpMat
            H ^ G : GrpMat, GrpMat -> GrpMat
            [Future release] Normalizer(G, H) : GrpMat, GrpMat -> GrpMat
            SylowSubgroup(G, p) : GrpMat, RngIntElt -> GrpMat
            pCore(G, p) : GrpMat, RngIntElt -> GrpMat

      Low Index Subgroups
            LowIndexSubgroups(G, R : parameters) : GrpMat, RngIntElt -> [ GrpMat ]
            Example GrpMat_LowIndexMatrixGroup (H21E16)

 
Quotient Groups

      Construction of Quotient Groups
            quo<G | L> : GrpMat, List -> GrpPerm, Map
            G / N : GrpMat, GrpMat -> GrpMat
            Example GrpMat_Quotient (H21E17)

      Abelian, Nilpotent and Soluble Quotients
            AbelianQuotient(G) : GrpMat -> GrpAb, Map
            ElementaryAbelianQuotient(G, p) : GrpMat, RngIntElt -> GrpAb, Map
            pQuotient(G, p, c) : GrpMat, RngIntElt, RngIntElt -> GrpPC, Map, SeqEnum, BoolElt
            NilpotentQuotient(G, c) : GrpMat, RngIntElt -> GrpGPC, Map
            SolvableQuotient(G): GrpMat -> GrpPC, Map
            PCGroup(G): GrpMat -> GrpPC, Map
            Example GrpMat_SpecialQuotient (H21E18)

 
Matrix Group Actions

      Orbits and Stabilizers
            u * g : ModTupElt, GrpMatElt -> ModTupElt
            y ^ g : Elt, GrpMatElt -> Elt
            y ^ G : Elt, GrpMat -> SetEnum
            OrbitBounded(G, y, b) : GrpMat, Elt, RngIntElt -> BoolElt, SetEnum
            Orbits(G) : GrpMat -> [ SetIndx ]
            LineOrbits(G) : GrpMat -> [ SetIndx ]
            OrbitClosure(G, S) : GrpMat, { Elt } -> GSet
            Stabilizer(G, y) : GrpMat, Elt -> GrpMat
            Example GrpMat_Orbits (H21E19)

      Orbit and Stabilizer Functions for Large Groups
            OrbitsOfSpaces(G, k) : GrpMat, RngIntElt -> SeqEnum
            NumberOfFixedSpaces(x, s) : GrpMatElt, RngIntElt -> RngIntElt
            Example GrpMat_OrbitsOfSpaces (H21E20)
            EstimateOrbit(G, U: parameters) : GrpMat, ModTupFld -> RngIntElt, RngIntElt, RngIntElt
            ApproximateStabiliser(G, A, U: parameters) : GrpMat, GrpMat, ModTupFld -> GrpMat, GrpMat, RngIntElt, RngIntElt, RngIntElt
            Example GrpMat_OrbitsOfSpaces (H21E21)
            StabiliserOfSpaces(Q) : Spaces -> GrpMat, SeqEnum
            Example GrpMat_StabiliserOfSpaces (H21E22)
            UnipotentStabiliser(G, U: parameters) : Grp, ModTupFld -> GrpMat, ModTupFld, GrpMatElt
            Example GrpMat_UnipotentStabiliser (H21E23)

      Action on Orbits
            OrbitAction(G, T) : GrpMat, Elt -> Hom(Grp), GrpPerm, GrpMat
            OrbitActionBounded(G, T, b) : GrpMat, Elt, RngIntElt -> BoolElt, Hom(Grp), GrpPerm, GrpMat
            OrbitImage(G, T) : GrpMat, Set -> GrpPerm
            OrbitImageBounded(G, T, b) : GrpMat, Set, RngIntElt -> BoolElt, GrpPerm
            OrbitKernel(G, T) : GrpMat, Set -> GrpMat
            OrbitKernelBounded(G, T, b) : GrpMat, Set, RngIntElt -> BoolElt, GrpMat
            Example GrpMat_Actions (H21E24)

      Action on a Coset Space
            CosetAction(G, H) : GrpMat, GrpMat -> Hom(Grp), GrpPerm, GrpMat
            CosetImage(G, H) : GrpMat, GrpMat -> GrpPerm
            CosetKernel(G, H) : GrpMat, GrpMat -> GrpMat
            Example GrpMat_CosetAction (H21E25)

      Action on the Natural G-Module
            GModule(G) : GrpMat -> ModGrp
            IsIrreducible(G) : GrpMat -> BoolElt, ModGrp
            SubmoduleAction(G, S) : GrpMat -> Map, GrpMat
            SubmoduleImage(G, S) : GrpMat -> GrpMat
            QuotientModuleAction(G, S) : GrpMat -> Map, GrpMat
            QuotientModuleImage(G, S) : GrpMat -> GrpMat
            IsAbsolutelyIrreducible(G) : GrpMat -> BoolElt
            AbsoluteRepresentation(M) : GrpMat -> GrpMat
            MinimalField(G) : GrpMat -> FldFin

 
Normal and Subnormal Subgroups

      Characteristic Subgroups and Subgroup Series
            Centre(G) : GrpMat -> GrpMat
            DerivedLength(G) : GrpMat -> RngIntElt
            DerivedSeries(G) : GrpMat -> [ GrpMat ]
            DerivedSubgroup(G) : GrpMat -> GrpMat
            [Future release] FittingSubgroup(G) : GrpMat -> GrpMat
            LowerCentralSeries(G) : GrpMat -> [ GrpMat ]
            NilpotencyClass(G) : GrpMat -> RngIntElt
            H ^ G : GrpMat -> GrpMat
            SolubleResidual(G) : GrpMat -> GrpMat
            SubnormalSeries(G, H) : GrpMat, GrpMat -> [ GrpMat ]
            UpperCentralSeries(G) : GrpMat -> [ GrpMat ]
            Example GrpMat_Series (H21E26)

      The Soluble Radical and its Quotient
            Radical(G) : GrpMat -> GrpMat
            RadicalQuotient(G) : GrpMat -> GrpPerm, Hom(Grp), GrpMat
            ElementaryAbelianSeries(G: parameters) : GrpPerm -> [ GrpPerm ]

      Composition and Chief Factors
            CompositionFactors(G) : : GrpMat -> [ <RngIntElt, RngIntElt, RngIntElt> ]
            ChiefFactors(G) : GrpMat -> [ <RngIntElt, RngIntElt, RngIntElt, RngIntElt> ]
            ChiefSeries(G) : GrpMat -> [ GrpMat ], [ <RngIntElt, RngIntElt, RngIntElt, RngIntElt> ]
            Example GrpMat_CompositionFactors (H21E27)

 
Coset Tables and Transversals
      CosetTable(G, H) : Grp, Grp -> Hom(Grp)
      Transversal(G, H) : GrpMat, GrpMat -> {@ GrpMatElt @}, Map

 
Presentations

      Generators and Relations
            FPGroup(G) : GrpMat :-> GrpFP, Hom(Grp)
            FPGroupStrong(G) : GrpMat :-> GrpFP, Hom(Grp)

      Matrices as Words
            WordGroup(G) : GrpMat -> GrpSLP, Map
            InverseWordMap(G) : GrpMat -> Map

 
Representation Theory
      LinearCharacters(G) : GrpMat -> [ Chtr ]
      CharacterTable(G) : GrpMat -> TabChtr
      PermutationCharacter(G, H) : GrpMat, GrpMat -> AlgChtrElt
      GModule(G) : GrpMat -> ModGrp
      GModule(G, A) : GrpMat, AlgMat -> ModGrp
      GModule(G, Q) : GrpMat, [ AlgMatElt ] -> ModGrp
      GModule(G, A, B) : GrpMat, GrpMat, GrpMat -> ModGrp, Map
      PermutationModule(G, H, R) : GrpMat, GrpMat, Rng -> ModGrp
      Example GrpMat_GModule (H21E28)

 
Base and Strong Generating Set

      Introduction

      Controlling Selection of a Base
            GoodBasePoints(G: parameters) : GrpMat -> []
            AssertAttribute(G, "Base", B) : GrpMat, MonStgElt, Tup ->
            HasAttribute(G, "Base") : GrpMat, MonStgElt -> BoolElt, Tup
            AssertAttribute(GrpMat, "FirstBasicOrbitBound", n) : Cat, MonStgElt, RngIntElt ->
            HasAttribute(GrpMat, "FirstBasicOrbitBound") : Cat, MonStgElt -> BoolElt, RngIntElt

      Construction of a Base and Strong Generating Set
            BSGS(G) : GrpMat ->
            RandomSchreier(G: parameters) : GrpMat ->
            ToddCoxeterSchreier(G) : GrpMat : ->
            Verify(G) : GrpMat ->

      Defining Values for Attributes
            AssertAttribute(G, "Order", n) : GrpMat, MonStgElt, RngIntElt ->
            AssertAttribute(G, "IsVerified", b) : GrpMat, MonStgElt, BoolElt ->
            HasAttribute(G, "Order") : GrpMat, MonStgElt -> RngIntElt
            HasAttribute(G, "IsVerified") : GrpMat, MonStgElt -> BoolElt

      Accessing the Base and Strong Generating Set
            Base(G) : GrpMat -> [Elt]
            BasePoint(G, i) : GrpMat, RngIntElt -> Elt
            BasicOrbit(G, i) : GrpMat, RngIntElt -> SetIndx
            BasicOrbitLength(G, i) : GrpMat, RngIntElt -> RngIntElt
            BasicOrbitLengths(G) : GrpMat -> [RngIntElt]
            BasicStabilizer(G, i) : GrpMat, RngIntElt -> GrpMat
            BasicStabilizerChain(G) : GrpMat -> [GrpMat]
            NumberOfStrongGenerators(G) : GrpMat -> RngIntElt
            StrongGenerators(G) : GrpMat -> SetIndx(GrpMat)

 
Soluble Matrix Groups

      Conversion to a PC-Group
            PolycyclicGenerators(G) : GrpMat -> [ GrpPCElt ]
            PCGroup(G) : GrpMat -> GrpPC, Map

      Soluble Group Functions
            pCentralSeries(G, p) : GrpMat, RngIntElt -> [ GrpMat ]

      p-group Functions
            IsSpecial(G) : GrpMat -> BoolElt
            IsExtraSpecial(G) : GrpMat -> BoolElt
            FrattiniSubgroup(G) : GrpMat -> GrpMat
            JenningsSeries(G) : GrpMat -> [ GrpMat ]

      Abelian Group Functions
            AbelianInvariants(G) : GrpMat -> [ RngIntElt ]

 
Matrix Groups of Large Degree

      Introduction

      Classical forms
            ClassicalForms(G): GrpMat -> BoolElt
            SymplecticForm(G) : GrpMat -> AlgMatElt
            ScalarsSymplecticForm(G) : GrpMat -> SeqEnum
            SymmetricBilinearForm(G) : GrpMat -> AlgMatElt
            ScalarsSymmetricBilinearForm(G) : GrpMat -> SeqEnum
            QuadraticForm(G): GrpMat -> AlgMatElt
            ScalarsQuadraticForm(G) : GrpMat -> SeqEnum
            UnitaryForm(G) : GrpMat -> AlgMatElt
            ScalarsUnitaryForm(G) : GrpMat -> SeqEnum
            FormType(G) : GrpMat -> MonStgElt
            Example GrpMat_ClassicalForms (H21E29)

      Recognizing Classical Groups in their Natural Representation
            RecognizeClassical( G : parameters): GrpMat -> BoolElt
            IsLinearGroup(G) : GrpMat -> BoolElt
            IsSymplecticGroup(G) : GrpMat -> BoolElt
            IsOrthogonalGroup(G) : GrpMat ->BoolElt
            IsUnitaryGroup(G) : GrpMat -> BoolElt
            ClassicalType(G) : GrpMat -> MonStgElt
            Example GrpMat_RecognizeClassical (H21E30)

      Primitivity Testing
            IsPrimitive(G: parameters) : GrpMat -> BoolElt
            BlockSystem(G) : GrpMat -> Rec
            BlocksImage(G) : GrpMat -> GrpPerm
            Example GrpMat_IsPrimitive (H21E31)

      Semilinearity
            IsSemiLinear(G) : GrpMat -> BoolElt
            DegreeOfFieldExtension(G) : GrpMat -> RngIntElt
            CentralisingMatrix(G) : GrpMat -> AlgMatElt
            FrobeniusAutomorphisms(G) : GrpMat -> SeqEnum
            WriteOverLargerField(G) : GrpMat -> GrpMat, GrpMat, GrpAb, SeqEnum
            Example GrpMat_Semilinearity (H21E32)

      Tensor Products
            IsTensor(G: parameters) : GrpMat -> BoolElt
            TensorBasis(G) : GrpMat -> GrpMatElt
            TensorFactors(G) : GrpMat -> GrpMat, GrpMat
            IsProportional(X, k) : Mtrx, RngIntElt -> BoolElt, Tup
            Example GrpMat_Tensor (H21E33)

      Tensor-induced Groups
            IsTensorInduced(G : parameters) : GrpMat -> BoolElt
            TensorInducedBasis(G) : GrpMat -> GrpMatElt
            TensorInducedPermutations(G) : GrpMat -> SeqEnum
            Example GrpMat_TensorInduced (H21E34)

      Decompositions with Respect to a Normal Subgroup
            SearchForDecomposition(G, S) : GrpMat, [GrpMatElt] -> BoolElt

            Accessing the Decomposition Information
                  Example GrpMat_Decompose (H21E35)
                  IsExtraSpecialNormalise(G) : GrpMat -> BoolElt
                  ExtraSpecialParameters(G) : GrpMat -> [RngIntElt, RngIntElt]
                  ExtraSpecialGroup(G) : GrpMat -> GrpMat
                  Example GrpMat_ExtraSpecial (H21E36)

      Writing Representations over Subfields
            IsOverSmallerField(G) : GrpMat -> BoolElt, GrpMat
            IsOverSmallerField(G, d) : GrpMat, RngIntElt -> BoolElt, GrpMat
            Example GrpMat_IsOverSmallerField (H21E37)

      Related Functions
            WriteOverSmallerField(G, F) : GrpMat, FldFin -> GrpMat, Map

 
Bibliography