--- title: "Magma V2.17-8 Patch Notes" canonical: "https://docs.magma-maths.org/patchnotes/2.17-8.html" source: "https://docs.magma-maths.org/patchnotes/2.17-8.md" --- # Magma V2.17-8 Patch Notes ## Algebras - A missing error check has been inserted. Reported by C. Quitte. ## Elliptic Curves - Allow [`QuarticReduce`](../ArithmeticGeometry/EllipticCurvesOverQAndNumberFields/mordell-weil.md#function-quarticreduce-rngupolelt) (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`](../FiniteGroups/AlmostSimpleGroups/properties-lie-groups.md#function-classicalsylow-grpmat-rngintelt) 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`](../FinitelyPresentedGroups/PolycyclicGroups/power-group.md#function-powergroup-grppc) 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`](../BasicRings/Integers/factor.md#function-getstoredfactors) returns the sequence of currently stored factors used in integer factorization. ## Lie Theory - Fix a problem in [`IsSplittingCartanSubalgebra`](../LieTheory/LieAlgebras/sub.md#function-issplittingcartansubalgebra-alglie-alglie) for matrix Lie algebras. - Add support for [`SplittingCartanSubalgebra`](../LieTheory/LieAlgebras/sub.md#function-splittingcartansubalgebra-alglie), [`IsSplitToralSubalgebra`](../LieTheory/LieAlgebras/sub.md#function-issplittoralsubalgebra-alglie-alglie), and [`SplitToralSubalgebra`](../LieTheory/LieAlgebras/sub.md#function-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`](../LieTheory/RepresentationsOfLieGroupsAndAlgebras/representation-properties.md#function-littlewoodrichardsontensor-pq) 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`](../MatricesLinearAlgebra/SparseMatrices/non-trivial.md#function-rowspace-mtrxsprs) 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.