Change log for Magma V2.22-5 (Released 30/9/2016)

Aggregates

·An intrinsic Components has been added for cartesian products.

Algebraic Function Fields

·An infinite loop in the GaloisGroup and Subfields computations for an algebraic function field defined as an extension of another algebraic function field by a polynomial with denominators has been stopped. Reported by R. MÃ¼ller.

Algebraic Number Fields

·A sequence with universe the number field of an order will no longer be coerced (if possible) into an element of the order when given as the RHS of the ext or ideal constructors. Reported by E. ThÃ³me.

·IsRootOfUnity was completely wrong for the case of cyclotomic fields using the sparse representation. Reported by T. Dokchitser.

·Norm(f) for a univariate polynomial f with coefficients in a field extension was wrong in general. Reported by J. Klueners.

·HilbertSymbol for number fields and prime ideals over 2 has been sped up considerably. Due to M. Kirschmer.

Coding Theory

·The AdditiveCode constructor that takes a linear code as input now ensures it is defined over a field.

·A problem with automorphisms of codes over Z/4Z was fixed.

Lattices

·The NaturalAction vararg for IsIsometric of totally definite number field lattices has had its restriction about ambient inner products removed. Noted by M. Kirschmer.

·A bug in the AutomorphismGroup function has been fixed. The bug was reported by M. Kirschmer.

Local Fields

·An ancient problem with Factorization over the p-adics was fixed. The problem was that a incorrect test was being used to test for squarefreeness of an auxiliary polynomial (the discriminant was used, when this could be 0 to the ambient precision without the polynomial itself having a repeated factor). This would cause occasional infinite loops. Reported by T. Dokchitser and J. Jones.

Modules

·Some bugs in IsIsomorphic for G-modules over the rational field have been fixed. Reported by C. Fieker.

Series Rings

·An improvement has been made to finding the roots of a polynomial over a series ring over a local field.

System

·Split no longer produces an empty first item if the string begins with a separator and IncludeEmpty is false (which is the default). Reported by T. Dokchitser.