Change log for Magma V2.28-3 (Released 29/8/2023)

Algebraic Number Theory

·IsIsomorphic now chooses coefficient embeddings that lead to subfield and isomorphism relationships over those that do not.

Arithmetic Geometry

·The function LSeries for Hilbert modular forms has been fixed when the precision is lifted by LSetPrecision (the ambient rings for the euler factors were not having their precision increased). Problem reported and fix provided by E. Costa.

·A bug in evaluating dirichlet characters with trivial modulus at zero has been fixed. Reported by E. Costa.

Commutative Algebra

·An incorrect result in Radical and related functions for ideals defined over algebraic function fields has been fixed. Reported by M. Grassl.

Group Theory

·A bug in NilpotentQuotient where incorrect results were given for very large quotients has been fixed. Reported by M. Newman, M. Vaughan-Lee and A. Previtali.

·A crash in IdentifyGroup for small groups has been fixed. Reported by M. Newman.

·Some of the matrices produced by ExtGenerators were not cocyclic because of an incorrect calculation of a basis for an abelian group. Bug identified by Primoz Potocniz.

·The package for computing with p-groups of tame genus has been updated by E. O'Brien.

Matrices

·A crash in SmithForm when the RHS transformation matrix alone is requested has been fixed. Reported by E. Costa.

·ExteriorPower(A, 0) now returns a 1x1 matrix. Issue reported by E. Rains.

·Some inefficiencies in certain types of matrix echelonization have been fixed. Reported by C. Rito.

Schemes

·The grading of a ProjectiveSpace is now transferred to the coordinate ring even when that grading contains a zero entry. Reported by C. Rito.

System

·Fixed a serialization bug when the same multivariate polynomial ring (or ideal) appears more than once in the object to be serialized or transmitted. The resulting serialization stream is invalid and the object is unable to be retrieved. Reported by L. Finotti.