Change log for Magma V2.28-6 (Released 9/2/2024)

Algebraic Geometry

·Some fixes in the code for Kodaira-Enriques classification of surfaces have been made. Provided by A. Logan and J. Voight.

Algebraic Number Fields

·A crash when computing norms of recursively defined orders has been fixed. Reported by J. Schleucher.

·A bug affecting the integrality of an IntegralBasis computed using the Montes algorithm has been fixed. Reported by P. Koprowski.

·Extends now handles relative extensions properly. Reported by J. Schleucher.

·An "Ambiguous signature match" has been removed. Reported by J. Schleucher.

Coding Theory

·A crash computing the automorphism group of an additive code has been fixed. Bug reported by M. Grassl.

Cohomology

·Two new functions for basic algebras have been added: IsSelfInjective and IsSymmetric. Request of Dave Benson; code supplied by Jon Carlson.

Finite Groups

·Incorrect identifications returned by IdentifyGroup for several finite groups have been fixed. Reported by D. Roe and fixed by E. O'Brien.

·A error, sometimes a crash, in MaximalSubgroups of the trivial group has been fixed. Bug reported by J. Jones as an error in DirectSumDecomposition.

Local Rings and Fields

·Element multiplication in an extension of a p-adic field has been fixed so that x*x has the same precision as x^2. Reported by M. Bright.

Matrices

·Removed spurious exclamation marks from Magma-level printing of sequences of matrix algebra elements.

·Error messages have been made more informative when matrix multiplication on a GPU runs out of memory. Reported by S. Stella.

Matrix Groups

·A new version of CompositionTree has been provided by E. O'Brien and installed. This fixes some minor cases where CompositionTree was failing and tweaks a small number of parameters related to CentraliserOfInvolution.

·A new function to recognise constructively alternating and symmetric square representations of classical groups has been installed. This was developed and prepared by Csaba Schneider. It is available as part of the existing intrinsic RecogniseSmallDegree.

·The list of all 22 maximal subgroups of the sporadic group Co1 are now included.

PC Groups

·A bug computing the automorphism group of an abelian pc-group has been fixed. Bug reported by E. O'Brien.

Quaternion Algebras

·A bug in the computation of tame orders of quaternion algebras has been fixed. Reported by A. Logan.

·A bug in FundamentalDomain has been fixed. Reported by J. Rickards.

Representation Theory

·Incorrect handling of Schur indices when splitting some kinds of homogeneous QG-modules has been fixed. Reported by J. Jones.

System

·The -e and -E options have been added to the help message when calling magma -h. Reported by M. Grassl.