Change log for Magma V2.17-13 (Released 5/11/2011)

Algebraic Function Fields

·A bug has been fixed when testing whether extensions with large exact constant fields are Kummer extensions.

Commutative Algebra

·A failure when computing Groebner bases in exterior algebras in characteristic zero has been fixed. Reported by M. Barakat.

·A crash in Shift for module complexes has been fixed.

Conics

·A small bug with ParametrizationMatrix when given an integral conic was fixed.

Elliptic Curves

·In ThreeDescent, Fisher's new method for trivializing the algebra has been switched on.

·A trivial mistake in EllipticCurve(C) for a quartic curve C has been fixed.

·The intrinsic Frobenius(P) for a point P over a function field did not work.

General Algebras

·Fixed an issue where a,b := HasOne(A); would fail if A were an algebra without one.

·Memory handling after QuaternionOrder reports an error has been improved.

Genus One Models

·The intrinsic Reduce new uses the new type TransG1; the Minkowski option now works. Reported by T. Fisher.

Groups

·A bug affecting the LowIndexSubgroups routine for pc-groups has been fixed. The effect of the bug was to return subgroups of index greater than the given limit. Bug reported by D. Frapporti.

·A bug in the OrderEqual filter for the Subgroups command has been fixed. Bug reported by A. Munemasa.

·A problem in the Evaluate function has been fixed. The function did not test that the number of values given was enough to assign values to all generators of the SLP group, leading to unpredictable results. This is now checked and results in a runtime error. Bug reported by J. Carlson.

Hyperelliptic Curves

·The intrinsic Involution now allows points over extensions. Reported by D. Kohel.

Lie Theory

·Fix for an issue where AdjointRepresentation of a group of Lie type would return a Lie algebra with some incorrect attributes.

Local Rings

·Checking of input for TeichmuellerSystem has been improved.

Number Fields

·An assertion failure in RealWeakApproximation has been fixed. Reported by B. Linowitz.

·A precison problem which caused solutions to be missed in some rare situations has been fixed. Reported by E. G.g Jimenez.

Residue Class Rings of Integers

·The intrinsic IsRootOfUnity now works for residue class rings of integers.

System

·The intrinsic ParallelSort now properly handles the case where both arguments are the same sequence. Reported by A. Kasprzyk.