Magma V2.17-8 Patch Notes

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 asLittlewoodRichardsonTensorOld`. 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.