Magma V2.12-20 Patch Notes

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.