Change log for Magma V2.13-12 (Released 11/5/2007)

Algebraically Closed Fields

·A bug in coercion into a polynomial ring over an algebraically closed field has been fixed. Reported by C. Bardavid.

Coding Theory

·A bug that caused the results of GriesmerMinimumWeightBound to be too high has been fixed. Reported by M. Kiermaier.

Elliptic Curves

·A bug when halving points on elliptic curves over fields of characteristic two has been fixed.

·The creation of elliptic curves from a hyperelliptic curve and a point should now return slightly nicer maps â€“ an approach for characteristic 2 was accidentally being invoked for all characteristics.

·A problem in TorsionSubgroup for curves over function fields has been sorted out.

Groups

·A bug in storing the subgroups of a group, giving incorrect results on a second call to Subgroups, has been fixed.

·A bug in AQInvariants applied to fp groups has been fixed. Reported by S. Humphries.

Lattices

·Some bugs in the LLL algorithm under Windows have been fixed. Reported by T. Dokchitser.

Matrices

·Bugs with matrix multiplication and echelonization over GF(pd) for p â‰¥ 256 and d â‰¥ 1 have been fixed.

·The algorithm for computing the characteristic polynomial of matrices over residue class rings has been fixed so that it does not take so much memory.

Matrix Groups

·A problem with computing the length of a real reflection group has been fixed.

Modular Forms

·A problem with Eisenstein series has been corrected.

·Errors with modular forms over p-adic fields, arising from relatively recent changes to p-adics, have been fixed.

·Several minor bugs have been fixed.

Number Fields

·A bug causing internal errors when testing if two relative extensions defined by non-integral polynomials are isomorphic has been fixed.

·A bug causing internal errors in the prime splitting in relative extensions defined by non-monic polynomials has been fixed.

·A bug causing runtime-errors when computing infinite places of relative extensions over complex number fields extended by polynomials in \matbb{Z} has been fixed.

·A bug in GaloisGroup of polynomials over number fields defined by a non-monic polynomial has been fixed.

·Calling AbsoluteValues of an element in a relative extension is now generating a runtime error rather than an internal error.

·Calling CompleteClassGroup (and similar functions) without a class group process being present caused internal errors. This has been changed to produce runtime errors instead.

·Calling DecompositionType with a negative (integer) prime now gives an error message instead of crashing.

·The minimal polynomial of the zero element of a sparse cyclotomic field of degree one no longer crashes. Reported by H. Johnston.

Polynomial Rings

·A crash in the factorization of the polynomial 1 over function fields has been fixed. Reported by F. Hess.

·A bug in polynomial multiplication, called by arithmetic for extensions of local rings, has been fixed.

·A coercion problem in Evaluate has been fixed. Reported by E. Rains.

System and Language

·Bugs in WriteBinary have now been fixed.