Change log for Magma V2.25-4 (Released 28/2/2020)

ALGEBRAS: Star Algebras

·An upgrade to the star algebras package developed by Peter A. Brooksbank, Joshua Maglione and James B. Wilson is included in this release. Intrinsics have been optimized and some bugs fixed.

·A missing check for algebra basis computation over inexact rings has been added. Reported by E. Assaf.

COMBINATORIAL THEORY: Graph Theory

·A crash related to the Vertices intrinsic function has been fixed. Bug reported by Tim Dokchitser.

GEOMETRY: Algebraic Geometry

·A check for ordinary projectiveness of the underlying scheme has been included for the divisor intersection intrinsics IntersectionNumber, SelfIntersection, Degree, IsNef and IsNefAndBig. The short descriptions of these intrinsics have also been updated to include the ordinary projective condition. Reported by Xavier Roulleau.

GEOMETRY: Polytopes

·The intrinsic NumberOfPoints which sometimes gives an incorrect result in the case of some rational (non-lattice) polytopes, has been fixed. Reported by A. Laface.

GROUP THEORY: Permutation Groups

·A crash when constructing a G-set has been fixed. Bug reported by E. Assaf.

·The degree-32 transitive group identification code that was accidentally commented out in version 2.25-3 has been reinstated. Reported by J. Jones.

MODULES AND VECTOR SPACES: Matrices

·An issue where the multiplication of two large integer matrices could incorrectly compute the resulting size, leading to memory exhaustion has been fixed. Reported by J. Balakrishnan.

MODULES AND VECTOR SPACES: Vector Spaces

·A bug in DirectSum for proper subspaces of embedded vector spaces has been fixed. Reported by E. Assaf.

NUMBER THEORY: Algebraic Number Fields

·The intrinsic CoprimeRepresentative now always returns an element of a field of fractions of an order. Reported by M. Pohst.

NUMBER THEORY: Galois Representations

·Tim Dokchitser has provided a fix for a bug in the intrinsic AbsoluteInertiaDegree which occurs when computing Galois representations for elliptic curves over 3-adic fields (wild case).

NUMBER THEORY: Hypergeometric Motives

·A problem with AlphaBetaData has been fixed. Reported by E. Costa.

NUMBER THEORY: Local Rings and Fields

·Testing IsNormal for finite precision rings has been fixed. Reported by T. Dokchitser.

SYSTEM: Printing

·Signature printing has changed slightly; now extra lines in definitions will be indented, and extra lines in descriptions will not be (further) indented.

SYSTEM: Types

·An issue where intrinsics using extended types with a user-defined type as a component might fail to be matched has been fixed