Change log for Magma V2.16-14 (Released 25/11/2010)

Algebraic Curves

·A bug in function fields of non-plane curves has been fixed. Reported by C. Quitte.

·A bug in CurveQuotient has been fixed that was returning incorrect answers or giving an error for quotients of hyperelliptic curves when the result is of genus 1 or occasionally when the result is of genus zero.

Coding Theory

·EuclideanWeightEnumerator was erroneously allowed to run on codes not defined over 4, and would crash as a result. This has now been fixed.

Commutative Algebra

·Some problems in Kernel and IsConsistent for matrices over polynomial rings and their localizations have been fixed. Reported by C. Quitte.

·The type checking in CommonEigenspaces and Diagonalization has been improved to allow number fields and cyclic fields, not just the more general algebraic fields. Reported by R. Zeier.

·A failure in Normalization when the ideal had large dimension has been fixed. Reported by O. Kedzierski.

·A problem in FreeResolution with degree 0 variables has been fixed. Reported by M. Reid.

Elliptic Curves

·A bug has been fixed in the simplified model computation for supersingular curves of characteristic two. Now the a2 coefficient is set to zero.

·A bug has been fixed in TatePairing that was giving an error if one of the arguments was the zero point. Reported by D. Kohel.

·A crash in EtaqPairing has been fixed.

Function Fields

·A problem in coercion into function fields has been fixed. Reported by E. Schost.

·A bug in Subfields for a function field whose maximal order had been computed first has been fixed. Reported by N. Bruin.

Groups

·A bug where attributes of a GrpAuto were deleted too soon has been fixed. Bug reported by D. Howden.

·A problem with the OuterFPGroup homomorphism associated with a GrpAuto, where this map refused to compute an inverse image when the outer automorphism group is trivial, has been fixed. Bug reported by M. Kirschmer.

·A bug in the Extension function for pc-groups, where elements of the automorphism group of the first argument were not accepted as valid input, has been fixed. Bug reported by K. Andersen.

·A bug in Subgroups, where some classes of subgroups were missed when OrderEqual or OrderDividing parameters were set, has been fixed.

·A crash in permutation group code computing intersections has been fixed. Bug reported by S. Humphries.

Lattice

·A bug giving incorrect results in ClosestVectors for a lattice with non-standard basis and non-trivial inner product has been fixed.

Lie Theory

·A problem in the arithmetic with representation decompositions was fixed. Reported by R. Zeier.

Modules

·A crash when using KMatrixSpaceWithBasis has been fixed. Bug reported by S. Humphries.

Number Fields

·A bug in the code for automorphism groups of linear extensions of Q has been fixed.

·IsAlgebraicField now returns true for specialised number fields such as cyclic fields and quadratic fields. Reported by R. Zeier.