Change log for Magma V2.27-9 (Released 8/5/2023)

Algebraic Number Fields

·RelativeField(F, F) now returns a linear extension of F as documented. Reported by J. Schleucher.

Commutative Algebra

·A bug in Kernel for matrices defined over a field of fractions of an affine algebra has been fixed. Reported by M. Cuntz.

·A crash in PrimaryDecomposition over rational function fields in higher characteristic (arising from computing divisors of points on schemes) has been fixed. Reported by M. Houben.

Galois Groups

·IsEasySnAn has been fixed when the input polynomial has non trivial denominators. Reported by N. Katz.

Lattices

·The function Orthonormalize has been improved so that it is more stable and gives a correct informative error message if there are precision problems. Issue reported by A. Budroni.

Matrices

·A bug in FrobeniusFormAlternating where the result did not satisfy the divisibility condition has been fixed. Reported by S. Hashimoto.

Representation Theory

·A bug in CompositionSeries for a QG-module when its irreducibity attribute was already set has been fixed. Reported by J. Feuerpfeil.

Sparse Matrices

·A crash in SetEntry when dynamically extending a sparse matrix while setting an entry to zero has been fixed. Reported by H. Yau.

Strings

·The versions of Position and index that take a starting offset have been moved into the kernel and are now substantially faster and more memory friendly.