Magma V2.13-12 Patch Notes

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 -- 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 $GF(p^d)$ for $p\ge 256$ and $d\ge 1$ 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.