V1.00-4 (19 May 1994)

Recent Changes and Improvements

Magma licence

  • Typing "magma -d" at the shell prompt dumps the Magma licence for the current magmapassfile.

    Character Theory

  • Improved version of the Dixon-Schneider algorithm implemented and installed.
  • New functions LinearCharacters and PrincipalCharacter.
  • All basic character functions re-engineered and many errors and limitations removed.
  • New functions SymmetricComponents, SymplecticComponents, OrthogonalComponents.

    Finite Fields

  • General arithmetic sped up for larger fields.
  • Fields of size up to about 2^100 have optimal representation.
  • Fields with non-primitive defining polynomials now fully optimized.

    Modules and Matrix Structures

  • CambridgeMatrix for large matrices in Cambridge format.
  • MatrixGroup(G-module) for constructing a matrix from the acting generators of a G-module.
  • ChangeRing(M, R) for any module M, ring R.
  • ChangeRing(A, R) for matrix algebra A, ring R.
  • DirectSum(M, N) for modules M, N returns embedding maps.
  • DirectSum(Q) for sequence Q of modules, returns sequences of maps.
  • ChangeRing(M, S, f) for any module M, ring S, hom f: ring(M) -> S.
  • ChangeRing(A, S, f) for matrix algebra A, ring S, hom f: ring(A) -> S.
  • RestrictField(G, S) for matrix group G (over K), and S subfield of K.
  • ExtendField(G, L) for matrix group G (over L), and L extension field of K.
  • ChangeRing(G, S) for matrix group G (over R), and S any ring.
  • ChangeRing(G, S, f) for matrix group G over R, S any ring, hom f: R -> S.
  • hom<A -> B | f> for full matrix algebras A & B, map f: ring(A) -> ring(B).
  • IsSymmetric(X), IsDiagonal(X) for matrix ring element X.
  • G-homomorphisms added -- types ModMatGrp and ModMatGrpElt.
  • IsGHom(X) - is X a GHom, for matrix X with dom and codom G-modules?
  • Hom(M, N) for RG-modules M and N, the module of all R-homs.
  • GHom(M, N) for RG-modules M and N, the module of all G-homs.
  • hom<M -> N | matrix> for modules M and N, the (map) hom given by matrix.
  • (H ! map) given hom module H and map, return matrix of map.

    Graphs

  • Memory usage improved.

    Polynomials

  • SplittingField(F) for univariate polynomial over a finite field.
  • SplittingField(S) for set of polynomials. Arrow pairs allowed in polynomial homomorphism constructor.
  • ChangeRing(A, S) for polynomial algebra A (over R), and S any ring.
  • ChangeRing(A, S, f) for polynomial algebra A (over R), and S any ring, map f: R -> S.

    Soluble groups

  • Generator names for PC groups are now used in the printing.
  • SystemNormalizer installed.
  • Access functions for elements of a conditioned PC group updated.
  • Recent Bug Fixes

    Character Theory

  • Many bug fixes in CharacterTable and other functions.

    Graphs

  • Bug in Girth fixed.
  • Bug in InsertVertex fixed.
  • Bug in union for graphs and digraphs fixed.

    Soluble groups

  • Bug in ChiefSeries fixed.


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