Change log for Magma V2.12-11 (Released 19/9/2005)

Algebraic Geometry

·Bugs in TangentCone, TangentLine, TangentSpace and ClassGroup for curves have been fixed. Reported by S Stamminger.

·A bug in Modules(seq) and Relations(seq) for sequences in the function field of a curve has been fixed.

Algebras

·Fixed a false error message with IsSemisimple and IsSimple, which falsely required the base field of the algebra to be a finite field (now allows fields of characteristic zero).

·Extended CharacteristicPolynomial, Trace, Norm, and RepresentationMatrix to work for arbitrary elements of associative algebras.

·Fixes have been made to the function CanonicalGenerators for Lie algebras.

Arithmetic Geometry

·A bug in the elliptic curve function HeightPairingMatrix has been fixed. The bug caused a run-time error when the function was called. Reported by Randall Rathbun.

·A bug in ReducedMinimalWeierstrassModel for hyperelliptic curves has been fixed.

·A Magma version of the Stein-Watkins database of (a selection of) elliptic curves having conductor up to 108 (136,924,520 curves) together with a preliminary Magma interface is released for the first time. The 2GB database may be downloaded from the optional databases area.

Function Fields

·Bugs in IsSquare and IsRoot for elements of function fields have been fixed.

Groebner Bases

·A bug in computing GrÃ¶bner bases over the integers (which would miss a GB element sometimes) has been fixed (reported by T. Fisher).

Group Theory

·A bug in the computation of subgroups of the trivial abelian group has been fixed.

·A bug with word groups associated to RandomProcessWithWords for matrix and permutation groups has been fixed. Bug reported by Mark Stather.

·A bug causing a crash using UnlabelledCayleyGraph has been fixed. Bug reported by D. Wanrooij.

Number Fields

·A bug in AbsoluteOrder of simple relative fields that could result in memory corruption has been fixed.

Real Field

·A precision problem in the computation of real and complex roots of essentially integral polynomials has been fixed. This bug would cause the root computation either not to return or to give error messages.

Rings

·Fixed a bug with Characteristic which gave a false answer for a quotient of a polynomial ring of several variables.

Symmetric Algebras

·An incorrect requirement for Tableaux has been fixed. Bug reported (with a fix) by Claude Quitte.

System

·When using the -r command line switch to start Magma with a restored workspace, the signal handler was not set. As a result, attempts to interrupt Magma using <ctrl>-c would terminate the Magma process.