--- title: "Magma V2.17-7 Patch Notes" canonical: "https://docs.magma-maths.org/patchnotes/2.17-7.html" source: "https://docs.magma-maths.org/patchnotes/2.17-7.md" --- # Magma V2.17-7 Patch Notes ## Abelian Extensions - The bound used internally to compute class groups of cyclotomic extensions has been increased. The old bound was too small for certain examples. ## Abelian Extensions of Function Fields - A bug in the computation of `RayResidueRing` (and hence `RayClassGroup` has been fixed. The bug resulted in too small groups to be returned. Reported by C. Weir. ## Coding Theory - A [`MinimumLeeWeight`](../CodingTheory/LinearCodesOverZ4/weight-distribution.md#function-minimumleeweight-code) attribute has been added for codes. ## Coherent Sheaves - A bug that was causing runtime errors in `IsIsomorphic` for coherent sheaves has been fixed. Reported by C. Quitte. ## Commutative Algebra - A problem in computing a free resolution of a graded module with negative weights has been fixed. Reported by C. Quitte. ## Elliptic Curves - Fixed a bug in [`CremonaReference`](../ArithmeticGeometry/EllipticCurvesOverQAndNumberFields/intro-2.md#function-cremonareference-db-crvell) that stopped it identifying non-minimal curves. Reported by E. G. Jiménez. - Calling `HeightPairingMatrix` on a null sequence no longer crashes. Additionally, a memory leak when specifying alternative precisions was fixed. - `EllipticCurve` now works for a hyperelliptic curve and a non-integral Weierstrass point. Reported by M. Stoll. - `IntegralPoints` occasionally missed points due to a trivial error, which has been fixed. - The Cremona database has been updated to include curves up to conductor 140000. ## Groebner Bases - An infinite recursion bug in the case of ideals with non-trivial gradings has been fixed. Reported by E. Rains. ## Group Characters and Representations - A runtime error when computing the character table of a matrix group over the ring of integers modulo m has been fixed. Bug reported by I.M. Isaacs. ## Groups - A crash due to memory management problems with left and right cosets of a permutation group has been fixed. - The orders of minus type, and all conformal, orthogonal groups are now stored with the group on creation. Omission reported by E. O’Brien. - A bug in `PCGroup` when applied to a pc-group has been fixed. Bug reported and fixed by D. Howden. - P. Brooksbank’s package for constructive recognition of SU3, SU4 and Sp4 in even characteristic has been updated. - A crash when applying `Evaluate` with 2nd argument a group automorphism group has been fixed. Bug reported by D. Howden. ## Lattices - A crash in `AutomorphismGroup` for lattices has been fixed. Reported by G. Bellot. - A crash in `AutomorphismGroup` for lattices has been fixed. Reported by G. Collinet. ## Lie Theory - Fixed a bug where [`ChevalleyBasis`](../LieTheory/LieAlgebras/operation.md#function-chevalleybasis) and related functions could fail due to an unlucky choice of random elements. - Fixed a problem where `MatrixLieAlgebra` (to make a Lie algebra from a normal matrix algebra) would return a matrix Lie algebra with too few elements. Bug reported by A. Previtali. - Changed the output of `CartanName` so that the string returned does no longer contain any trailing whitespace. - Fixed a problem in `DirectSum` for root data that resulted in crashes in the algorithms for representation decompositions and in [`ReductiveType`](../LieTheory/LieAlgebras/operation.md#function-reductivetype-alglie) for Lie algebras. Bug reported independently by W. de Graaf and R. Zeier. - Fixed a crash in `SymmetricPower` for representation decompositions of non-semisimple root data. Bug reported by W. de Graaf. - Fixed a number of memory leaks in the algorithms for calculating with representation decompositions. - Fixed a number of bugs in the construction of representations for non- semisimple groups of Lie type (in particular those returned by the `AdjointRepresentation` and `StandardRepresentation` intrinsics) where the map returned would not be a homomorphism. - A bug in `HighestWeightModule` and `HighestWeightRepresentation`, occurring in certain cases due to incompatibility of root orders, has been fixed. Bug reported and fix provided by W. de Graaf. ## Local Fields - The strategy in `SplittingField` for exact polynomials over local rings has been changed to avoid unneccessary precision loss. Reported by T. Dokchitser. - `SplittingField` for exact polynomials over local rings now supports a parameter to not compute a optimized presentation of the result to avoid precision problems. - `HenselLift` of a root of a polynomial over a p-adic field to a default precision no longer returns roots to the wrong precision. Reported by T. Matev. ## Matrix Algebras - Fix the function `Ngens` for matrix algebras of degree 0. Bug reported by A. Previtali. ## Number Fields - Calling `MaximalOrder` with the `Disriminant` parameter and a non-monic defining polynomial exposed an internal error. Reported by N. Bruin. - The calculator exhibited a problem in the `sub<|>` constructor for number fields: in fields with too many small degree subfields it occaisonly failed to find a primitive element. - In some strange circumstances, the regulator computed using `Regulator` of some order was wrong due to badly chosen internal precision. ## Polynomial Rings - A crash involving `IsSymmetric` has been fixed. Reported by N. Bruin. - A bug in polynomial squaring over non-commutative rings has been fixed. Reported by A. Previtali. ## Polytopes - Added the intrinsic [`IsIntegrallyClosed`](../Geometry/Polytopes/cones-polyhedra.md#function-isintegrallyclosed-torpol). Requested by G. Hegedüs. ## Power Series - A crash has been fixed when dividing power series defined over a ring without a division algorithm. ## Quaternion Algebras - `IsPrincipal` is now allowed for ideals over rings of type RngQuad and RngUPol. - Fixed `IsIsomorphic` when twosided and onesided ideals where mixed. ## Symmetric Function Algebras - Printing of symmetric functions as coefficients of polynomials or series has been improved to appropriately bracket the terms. ## System - Printing expressions in the debugger now works when reference parameters to procedures are involved. Reported by D. Howden. ## Tuples - An oversight in the deletion of tuples which could cause internal errors in rare situations has been fixed.