Change log for Magma V2.12-18 (Released 11/1/2006)

Algebraically Closed Fields

·Bugs in AbsolutePolynomial for ACFs with only one relation and in the function AbsoluteAffineAlgebra have been fixed. Reported by S. Murray.

Commutative Algebra

·A very rarely occuring crash in the F4 algorithm over small prime finite fields has been fixed.

·A serious inefficiency in testing whether affine algebras are fields has been fixed. Reported by D. Schmidt.

Elliptic Curves

·A typo has been fixed in the intrinsic HasComplexMultiplication so that it now behaves correctly for elliptic curves over Q. Reported by Christian Wuthrich among others.

Group Cohomology

·A bug that occurs when extending a soluble group by the trivial group has been fixed (function ExtensionsOfSolubleGroup). Reported by K Andersen.

Hyperelliptic Curves

·A bug in the point search for Jacobians of hyperelliptic curves that could cause random memory to be overwritten has been fixed.

Infinities

·Min and Max now work on sequences consisting solely of infinite elements (Â±Infinity()).

Integer Factorisation

·Some leaks in the ECM code have been fixed.

Lattices

·A bug when creating sublattices generated by a very large number of vectors has been fixed. Reported by A. Munemasa.

Lie Theory

·The functions WeightLattice and CoweightLattice and functions which depend on these have been fixed to be in agreement with the documentation.

·Infinite recursion in CartanSubalgebra for matrix lie algebras has been removed.

Matrices

·A crash in RationalReconstruction for matrices has been fixed. Reported by M. Grassl.

Matrix Algebras

·Error checks for left-ideal/right-ideal have been inserted for matrix algebras.

Number Fields

·A change in the handling of requests for Subfields of degree greater than the field degree has introduced: instead of generating an error, the empty sequence is returned.

·In NormEquation for number fields, the handling of the internal precision was changed. This fixed a bug reported from Linz.

·A rare case of wrong deletion of elements of number fields has been fixed. This bug could only occur when non-simple and simple number fields were used simultaneously.

·A problem in the processing of the arguments of Modinv made the function inaccessible for order of quadratic fields, number fields and cyclotomic fields. As a result, this broke the ClassGroup fuction for quadratic forms.

Permutation Groups

·A bug in evaluation of the class map for small permutation groups after intermediate calculations with the group has been fixed. Reported by J. Bray.

Polynomial Rings

·A bug when calling Roots of an integral polynomial and a real field has been fixed. Reported by W. Bosma.

·A crash in multivariate factorization over  has been fixed. Reported by M. Grassl.

Representation Theory

·The function GModule taking a representation map has been fixed to respect the order of the group generators. Reported by D. Holt.