Change log for Magma V2.28-4 (Released 6/12/2023)

Algebraic Number Theory

·Error checking has been improved for the ext constructor when the Abs parameter is true.

Algebras

·A crash in CompositionSeries for finite-dimensional algebras in characteristic zero has been fixed. Reported by A. Previtali.

Coding Theory

·Fixed a bug where IsQuasiCyclic, IsQuasiTwistedCyclic, or IsQuasiSimpleTwistedCyclic might erroneously return false. Reported by M. Grassl.

·MinimumWeight should no longer select enumeration as the policy when the problem space is too large to enumerate. Some minor tinkering has also been done with the policy for deciding whether to enumerate quantum codes or not.

Commutative Algebra

·The function IsPrime has been improved so that several classes of ideals are proven to be non-prime much more quickly than previously. Sample inputs given by M. Reid.

·Some problems when computing Groebner bases over prime finite fields with size around 60 bits have been fixed. Reported by M. Grassl.

Group Theory

·A missing case for SL in IsClassicalCentralizerApplicable has been added.

·The output of MaximalSubgroups is now sorted by order (from smallest to greatest).

·Some crashes (involving free FP groups) in pQuotient and ElementaryAbelianQuotient have been fixed. Reported by E. O'Brien.

·A bug which caused NilpotentQuotient to return incorrect answers in some large examples has been fixed.

·A crash which occured when applying a homomorphism from an abelian group to a permutation group has been fixed. Reported by E. O'Brien.

·Computing the quotient of a permutation group by the trivial subgroup is now treated as a special case, rather than using the generic methods. This may save a lot of time. Reported by E. O'Brien.

System

·The -i and -I options have been added to allow magma to be used as the interpreter in the #! line of a UNIX script.

·The -e and -E options have been added to allow magma to execute the remaining arguments as though they were magma input.