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Patch Notes

Magma V2.12-18 Patch Notes

Patch release for Magma V2.12-18. Updated areas: Algebraically Closed Fields, Commutative Algebra, Elliptic Curves, Group Cohomology, Hyperelliptic Curves and 10 more.

15 areas

Algebraically Closed Fields

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 $\mathbb{Q}$. 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 ($\pm$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

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 $\mathbb{Z}$ 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.
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