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Patch Notes

Magma V2.13-11 Patch Notes

Patch release for Magma V2.13-11. Updated areas: Algebraic Geometry, Algebras, Coding Theory, Commutative Algebra, Elliptic Curves and 9 more.

14 areas

Algebraic Geometry

  • A bug in pullbacks by maps between curves has been fixed. Reported by B. Smith.
  • Several redundant subset intrinsics have been removed. This fixes an ambiguous signature match when testing whether an indexed set of points is contained in a scheme. Reported by B. Smith.
  • A bug in the parametrisation of rational plane curves has been fixed.
  • A bug in ShortBasis for divisors on curves has been fixed. Reported by M. Grassl

Algebras

  • The action of a matrix on an element of a free algebra or quotient thereof now works properly. Bug reported by E. Rains.

Coding Theory

  • A bug that caused at most one cyclic generator matrix to be used during minimum weight computations has been fixed. Reported by M. Grassl.
  • HasLinearGrayMapImage now works for the zero code. Bug reported by M. Villanueva.
  • A bug that caused the results of GriesmerMinimumWeightBound to be too high has been fixed. Reported by M. Kiermaier.

Commutative Algebra

  • The Hilbert polynomial/series functions have been speeded up. This affects several other functions, like Degree for projective schemes.

Elliptic Curves

  • The code for IsDivisibleBy or DivisionPoints as applied to a point in the kernel of reduction of an elliptic curve over a p-adic field has been updated. There is now a much smaller loss in precision if all division points are required and some exist which do not reduce to 0.
  • Point functions IsWeaklyEqual and IsWeaklyZero have been added. These test for weak equality/nullity of points over a variable precision p-adic field. Over an exact field, they are the usual equality/zero checks.

Graded Rings

  • A bug in the printing of graded rings has been fixed. Reported by B. Smith.

Groups

  • A bug in IsConjugate for two elements of a pc-group, when the elements are not contained in the conjugating group, has been fixed. An incorrect conjugating element was being returned.
  • A bug computing image and kernel of a group homomorphism when the codomain is not a permutation or matrix group has been fixed. Reported by Eamonn O'Brien.
  • A bug when computing MaximalSubgroups of Alt(49) has been fixed. Bug report from Colva Roney-Dougal, fix by Derek Holt.
  • A crash when Subgroups is called on a PC-group with parameter OrderEqual set to a non-divisor of the group order has been fixed.

Integers

  • A bug that caused a crash when ECPP fails has been fixed.

Lattices

  • The function IsIsometric has been fixed so that it does not crash or return an incorrect answer when only a proper isometric embedding is found.

Matrices

Module Theory

  • A bug in decomposition of algebras has been fixed. Reported by D. Gruenewald.

Number Fields

  • A bug in NormEquation over number fields that would, in certain trivial cases, trigger a runtime error, has been fixed.
  • A bug in Completion of number fields that could in certain cases cause runtime errors has been fixed.

Polynomial Rings

  • A bug in multiplication in polynomial quotient rings over integer residue rings has been fixed. Reported by H. Hubrechts.
  • A crash in the factorization of the polynomial 1 over function fields has been fixed. Reported by F. Hess.
  • A coercion problem in Evaluate has been fixed. Reported by E. Rains.

System

  • Added a %O format code to the various printf-style directives and intrinsics. This enables a print level to be specified for the object. e.g., printf "%O\n", X, "Minimal";
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