Change log for Magma V2.15-14 (Released 26/9/2009)

Algebraic Geometry

·A memory leak in Saturate has been removed.

Coding Theory

·A crash in SternsAttack has been fixed. Reported by R. Niebuhr.

Commutative Algebra

·Crashes in the function CohomologyDimension (related to Regularity) and Twist have been fixed. Reported by E. Rains.

Cyclotomic Fields

·A memory problem occuring in the case of a sparse cyclotomic field of small degree where the conductor is a large integer, has been fixed.

Graphs

·A problem in graphs when nauty data was not present has been fixed. Reported by D. Leemans.

Groups

·A crash in FPGroup when applied to a regular permutation group has been fixed. Bug reported by S. Humphries.

·A problem defining homomorphisms with domain an abelian group having some trivial generators has been fixed. Previously this generated a runtime error.

·A problem with the group name used by the print option of pQuotient has been fixed. The problem was caused by a recent bug fix. Reported by G. Havas.

·A crash in the matrix groups base and strong generating set code has been fixed. Bug reported by M. Giudici.

Groups of Lie type

·RelativeRootElement was incorrectly trying to coerce its output into the twisted group.

·Order was giving incorrect values when the group was constructed from a root subdatum with smaller root space than the original root datum.

·Kernel works for homomorphism from a group of Lie type which is known to be injective.

·IsSimple has been implemented for groups of Lie type. The intrinsic IsIrreducible is now deprecated for this type.

Number Fields

·A string of problems with non-simple extensions defined over a number field having a non-integral denominator have been fixed. Without this fix an internal error would be triggered.

Polynomial Rings

·A problem with non-unique elements in polynomial quotient rings has been fixed. Reported by M. Stoll.

·A crash in powering of elements in a chain of recursive rings has been fixed. Reported by M. Stoll.

Representation Theory

·A bug in SymmetricRepresentation (which computes an irreducible module for a symmetric group), which occurs when the non-Specht algorithm is used, has been fixed; the matrices being returned were acting on the left rather than the right as Magma expects. Reported by M. Wildon.