Change log for Magma V2.12-20 (Released 17/3/2006)

Abelian Extensions of Number Fields

·A bug in NormEquation caused internal errors whenever the abelian extension was trivial. This has been fixed.

·In certain cases NormEquation would return elements rather than lists of elements. This has been fixed.

Arithmetic Geometry

·A bug in counting points on genus 1 hyperelliptic curves has been fixed.

·Ambient spaces of dimension 0 have been allowed since they are used in Chabauty.

Complex Fields

·Memory handling in Eisenstein and related functions has been fixed.

FP Lie algebras

·A missing error check for NilpotentQuotient has been inserted. The relations are also made monic.

Function Fields

·Automorphisms for function fields now generates better error messages when the automorphisms of the base field cannot be computed.

Groups

·A memory problem that occurred when constructing a homomorphism from a matrix group but with illegal images has been fixed. Bug reported by Markus Grassl.

·A memory problem within SylowSubgroup for permutation groups has been fixed.

·A problem with RandomProcess for permutation and matrix groups, where the Generators parameter may have been ignored, has been fixed.

·A bug in IdentifyAlmostSimpleGroup for matrix groups has been fixed.

Lattices

·A bug in IsIsometric has been fixed. Reported by M. Kirschmer.

·A bad error which caused lattice automorphism and isometry computations to run very slowly has been fixed. Reported by G. Nebe.

·A bug in OrthogonalDecomposition, which returned a decomposition of a proper sublattice, has been fixed. Reported by I. Middleton.

Lie Theory

·The creation of Coxeter groups has been made more efficient.

Number Fields

·A memory corruption problem in IsIsomorphic could result in incorrect results and internal errors. This has been fixed.

·The computation of Galois groups of constant polynomials would trigger an internal error and corrupt the memory. Constant polynomials have now been disallowed from GaloisGroup.

·A bug when using ext to extend a number field by a reducible polynomial has been fixed. Rather than triggering an internal error, the correct runtime error is now generated.

·SUnitGroup now returns a (usually) unassigned third result, so that regardless of the Raw parameter the result can be assigned to three variables.

Polynomial Rings

·A hanging problem in factorization of polynomial rings over polynomial quotient rings has been fixed. Reported by D. Schmidt.

Quadratic Fields

·IsPrincipal when applied to non-primitive ideals in quadratic fields would wrongly return an generator for the primitive part of the ideal rather than for the ideal. This has been fixed.

·In non-cyclic class groups of quadratic fields the discrete logarithm function could fail generating arbitrary errors, this has been fixed.

Ring of Integers

·A crash in the ECM code while factoring a special class of integers has been fixed.

·A crash in the ECPP code while proving primality of a special class of integers has been fixed.