Change log for Magma V2.28-14 (Released 14/10/2024)

Algebraic Function Fields

·Equality of zero and an element in product representation has been fixed. Reported by R. Hernandez.

·The input to some Image, Preimage etc intrinsics has been tightened to reflect the maps these intrinsics were implemented for. Reported by D. Zureick-Brown.

·Testing IsIsomorphic for 2 function fields has been fixed to match Isomorphisms. Reported by K. Kedlaya, J. Lau and Y. Huang.

Commutative Algebra

·An obscure crash in Groebner basis computation over the rational field has been fixed. Reported by F. Szollosi.

·A missing error check for module operations over non-supported polynomial rings has been added. Reported by M. Reid.

Finite Fields

·The function RootOfUnity has been improved for finite fields so that factorization of the order of multiplicative group of the extension field is now avoided. Issue reported by M. Grassl.

Forms

·OrthogonalReflection is no longer restricted to vectors from a quadratic space.

·A bug in eigenvalue computation when computing an Eigenform for Hilbert modular forms has been fixed. Reported by E. Costa.

Galois Groups

·Computing GaloisSubgroup for subgroups of a Galois group computed using complex roots has been fixed to avoid returning polynomials which are powers. Reported by R. van Bommel.

Groups

·A crash computing the order of the AutomorphismGroup of an infinite abelian group has been fixed. Bug reported by M. Watkins.

·A crash computing preimages under a homomorphism into a group automorphism group has been fixed. Bug reported by D. Roe.

·A situation where an embedding map into a SemidirectProduct had the wrong image has been fixed. Bug reported by D. Roe.

·Various crashes on assertions in the code for CharacterTable have been fixed. Reported by D. Roe.

Integer Residue Rings

·A crash in automatic coercion involving ideals of integer residue rings has been fixed. Reported by L. Jose.

Integer Ring

·The function MPQS has been fixed so that factors are now stored. Issue reported by M. Grassl.

Language and System

·New handling of MAC addresses was added to allow Magma to run under macOS Sequoia with MAC address randomisation turned on.

·A missing error check has been added for the case that type E is not a a user type for the user type declaration declare type T[E]; in package code.

·A comma-separated list with N expressions is now allowed for the right-hand-side (RHS) of an assignment statement, when the number of lvalues on the left to be assigned equals N. The expressions on the RHS are all evaluated first before any assignment on the left. For example, the following statement can now be used to swap variables a and b:

·a, b := b, a; 

·Note that for each expression on the RHS which has multiple return values, all those values are discarded except for the first. For example, the following statement will set a to 1 and b to 7 (only the first return value is used for each call of Quotrem):

·a, b := Quotrem(13, 10), Quotrem(75, 10);

Lie Theory

·For all intrinsics that return a Coxeter group and whose first argument is a category, there is now a check to ensure that the category is a valid type for Coxeter groups.

·StandardRepresentation and IsIsomorphic (of Lie algebras) have been fixed so that they no longer call HasPreimageFunction.

Matrices

·A memory leak affecting ElementaryDivisors and SmithForm has been fixed. Reported by M. Grassl.

·An obscure occasional crash in ElementaryDivisors has been fixed.