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Magma V2.17-8 Patch Notes

Patch release for Magma V2.17-8. Updated areas: Algebras, Elliptic Curves, Function Fields, Groebner Bases, Group Characters and Representations and 9 more.

14 areas

Algebras

  • A missing error check has been inserted. Reported by C. Quitte.

Elliptic Curves

  • Allow QuarticReduce (of 2-covers) to work on cubic inputs more readily. Reported by T. A. Fisher.

Function Fields

  • Maximal order computation in Artin–Schreier extensions has been improved.

  • Construction of Function fields using polynomials over non-fields has been expanded and fixed.

Groebner Bases

  • A crash involving a very large number of input polynomials has been fixed. Reported by F. Levy-dit-Vehel.

Group Characters and Representations

  • An error when computing the character table of a few groups where the full character table was not found has been fixed.

  • It is now possible to conjugate a character of group G by an element of of the automorphism group of G without getting a crash.

Groups

  • A bug in ClassicalSylow applied to a 2 dimensional unitary group has been fixed. Bug reported by E. O’Brien.

  • A crash in the evaluation of homomorphisms with domain a matrix group has been fixed. Bug reported by T. Dokchitser.

  • A bug when using sets of pc-groups with universe PowerGroup of a specified supergroup has been fixed. Bug reported by D. Howden.

  • A crash when computing double cosets in an fp-group, where one of the subgroups is the whole group, has been fixed.

  • A crash when using the class action map of a group automorphism group has been fixed. Bug reported by D. Howden.

  • A crash when computing image and/or kernel of a badly defined group homomorphism has been fixed. Bug hit by unknown calculator user.

  • Group homomorphisms with domain a rewrite system or automatic were broken and are now fixed. Bug reported by D. Holt.

  • A new version of the matrix group composition tree code from E. O’Brien has been installed.

Integer Ring

  • A new function GetStoredFactors returns the sequence of currently stored factors used in integer factorization.

Lie Theory

  • Fix a problem in IsSplittingCartanSubalgebra for matrix Lie algebras.

  • Add support for SplittingCartanSubalgebra, IsSplitToralSubalgebra, and SplitToralSubalgebra for matrix Lie algebras. Omission reported by A. Previtali.

  • Improved the interface to the Littlewood-Richardson tensor procedures for Lie representation decompositions (aka ``weight multisets’’), and add a number of checks. In particular, LittlewoodRichardsonTensor now either takes partitions (or partition multisets) and returns a partition multiset; or it takes two weight multisets and returns a weight multiset; or it takes a root datum and two highest weights and returns a weight multiset. The old (incorrect) behaviour remains temporarily available as LittlewoodRichardsonTensorOld. Crash reported by C. Quitte.

Matrices

  • Solution and Rowspace now work properly for matrices over exterior algebras. Reported by M. Kirschmer.

Matrix Algebras

  • Fix a bug in meet for matrix algebras that could occasionally lead to a crash due to an incorrect return type.

Permutation Groups

  • The transitive group database for degree 32 has been added.

  • Some minor leaks in the conjugacy classes computations for permutation groups have been fixed

Polynomial Rings

  • A missing error check for overflow in polynomial powering has been added.

Series Rings

  • A check has been added in Log to check whether the logarithm of the first coefficient can be taken. Reported by E. Thome.

  • Some precision handling in extensions of series fields has been improved when precision of an element is infinite.

System

  • A crash when recovering from runtime errors has been fixed. Reported by C. Puodzius.

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