Change log for Magma V2.23-8 (Released 9/2/2018)

Galois Groups

·The computation of subfields and Galois groups was improved by a refined cycle type analysis.

·An infinite loop has been broken in the computation of a prime, which does not divide the discriminant of the defining polynomial of any subfield, to use in the computation of a Galois group of a polynomial over a function field. Reported by R. MÃ¼ller.

Graphs

·The MaximumMatching of an edgeless graph no longer crashes.

Hyperelliptic Curves

·A possible crash when trying to make sequences of tuples containing points from incompatible hyperelliptic curves has been fixed.

Lattices

·Some difficulties with spinor genera have been fixed by M. Kirschmer. The problems arise from differences between the notion of Cassels (thus Conway-Sloane) of "spinor genus", which is more often called the proper spinor genus. The SpinorGenerators intrinsic now has a Proper vararg (by default true) to help with issue, but a more complete overhaul is still necessary. Reported by A. Haensch.

·The Genus intrinsic now properly considers denominators.

Linear Systems

·A crash in the application of the PolynomialMap of a Linear system to a sequence of vectors has been fixed.

Local Fields

·A bug with Coordinates over the p-adics was fixed. Reported by A. Rahm.

·A bug in testing whether a polynomial is inertial has been fixed.

Polynomial Rings

·A problem with denominator handling with mulvariate polynomials defined over relative number fields has been fixed. Reported by M. Grassl.

·Some problems in computing complex roots of real polynomials have been fixed. Reported by E. Sertoz and J. Jones.

·Fixed a crash when finding the variety of an ideal via exhaustive search, arising when there were no points in the variety.

·A missing error check has been included to ensure that divisors are non zero when using div.