Change log for Magma V2.19-3 (Released 1/2/2013)

Aggregates

·Fixed a bug in multiset constructors that could cause a later item in the constructor to replace an earlier one rather than augment it. This would only apply when the later item caused the multiset universe to enlarge and both items have the same value in this larger universe.

·Fixed a potential memory leak when using associative arrays and indexed assignments in such a way that the associative array's universe needs to change.

Algebraic Number Fields

·A bug in the computation of Subfields of a number field defined by a non-monic polynomial has been fixed.

Clifford Algebras

·A crash in CliffordAlgebra due to a missing universe for a null sequence has been fixed. Bug reported by Markus Kirschmer.

Coding Theory

·Fixed occasional excessive memory use when constructing large linear codes. This could also show up when making subspaces of vector spaces.

·Improved internal memory handling used by Words for codes of large dimension.

·A bug in Words which occasionally included the zero vector has been fixed. Reported by P. Lisonek.

·Fixed the name of the vararg NumWords in the descriptions of some intrinsics (was erroneously given as Cutoff).

·Fixed a very minor memory leak in NumberOfWords.

Commutative Algebra

·A bug in Radical has been fixed. Reported by E. Rains.

Cyclotomic Fields

·A crash in RootOfUnity when the degree of the field is less than half the order of the field has been fixed.

·An error in the MultiplicativeGroup map has been fixed. This has fixed a crash in computing AbsolutelyIrreducibleModules of a pc-group which was reported by Eamonn O'Brien.

Forms

·Code to construct the Wall form of a unitary matrix, which was missing from the main release, is now included.

Graphs

·A crash in EquitablePartition has been fixed.

Groups

·A crash computing normal subgroups of a permutation group has been fixed. Bug reported by Peter Mueller.

·An error in the stored order of a NormalClosure within permutation groups has been fixed. Bug reported by Peter Mueller.

·An crash when computing the Core of a subgroup of a permutation group has been fixed. Bug reported by Peter Mueller.

·A crash when computing IrreducibleModules of pc-group has been fixed. Bug reported by Primoz Potocnik.

·A crash when computing DistinctExtensions of pc-group has been fixed. Bug reported by Primoz Potocnik.

·A problem when computing normalizers of matrix subgroups has been fixed. This has improved computing subgroups of a matrix group in some cases

·A crash in Descedants of a p-group has been fixed. Bug reported by Michael Bush.

·A new parameter MaxAuts ahs been added to GeneratepGroups and Descendants to compute maximally automorphic descendants. Code supplied by Eamonn O'Brien.

·An error/crash when computing conjugacy classes of a general linear group has been fixed. This bug was reported, as a crash in PermutationCharacter, by Alex Bartel.

·A crash computing MaximalSubgroups has been fixed. Bug reported by Andreas-Stephan Elsenhans.

Lattices and Quadratic Forms

·A bug with WittInvariants and allied intrinsics was fixed, where the bad primes were computed from the determinant, and when the matrix was over the rationals, this need not be correct. Reported by Stefan Hoeppner.

Lie Theory

·A crash when computing WeightsAndMultiplicities of a root datum has been fixed. Bug reported by Emmanuel Kowalski.

·A crash in the Plethysm function has been fixed. Bug reported by Robert Zeier.

Modules

·A bug in hom for non-free modules has been fixed. Reported by M. Bright.

Quaternion Algebras

·A bug in the computation of normalizers of definite quaternion orders over number rings has been fixed.