Change log for Magma V2.28-15 (Released 18/10/2024)

Algebraic Number Fields

·An ambiguous signature match error for Evaluate applied to a matrix defined over a number field and a place has been fixed.

Commutative Algebra

·A very rare crash in RadicalDecomposition in finite characteristic has been fixed. Reported by Eamonn O'Brien.

·An obscure incorrect result for Variety for multivariate polynomial ideals defined over finite fields has been fixed. Reported by Eamonn O'Brien.

·A case where the Groebner Walk was hanging on ideals with unusual monomial orders has been fixed. Reported by Eamonn O'Brien.

·Some leaks in Groebner basis computation in characteristic zero have been fixed. Reported by Ferenc Szollosi.

Finite Fields

·The function IrreducibleLowTermGF2Polynomial(d) has been fixed to use the larger external database (also called by IrreduciblePolynomial(GF(2), d)) so that the upper limit on d is now 120016. Issue reported by Jonathan Love.

Geometry

·A bug in AdmissiblePair in the local Galois representation associated to a modular form has been fixed. Reported by Nuno Freitas.

·A bug in Eigenform for Hilbert modular forms has been fixed. Reported by Gonzalo TornarÃ­a.

Groups

·A bug where IsSatisfied with target an automatic group was disabled has been fixed. Reported by Stefan Witzel.

·A bug in computation of preimages of subgroups using a matrix group change ring homomorphism has been fixed.

·A crash in IdentifyGroup has been fixed. Reported by Eamonn O'Brien.

·A crash computing the class map and power map of a permutation group has been fixed. Reported by David Roe.

·An error in AutomorphismGroup for pc-groups has been addressed. Reported by David Roe.

·A crash using Relators on an fp-group defined by a coset-table has been fixed. Reported by Stefan Witzel.

Lie Theory

·The implementation of StandardRepresentation for Lie algebras and groups of Lie type has been revised so that it correctly handles root data of composite type and root data where the root order is not 'canonical'. Thus the bug that occurred when StandardRepresentation was applied to the group returned by SubsystemSubgroup has been fixed. Reported by David Craven.

Matrices

·A bug has been fixed involving subtraction of a scalar matrix and a matrix over GF(2). Reported by Lewis Combes.

Matrix Groups

·A bug in AreGLConjugate for matrix groups defined over the integer ring (where false was incorrectly returned for some conjugate groups has been fixed. Reported by Stefano Marseglia.

·A crash in UnitGroup for trivial matrix groups has been fixed.

Quaternion Algebras

·Magma level printing for quaternion algebras defined over number fields has been improved.