--- title: "Magma V2.15-11 Patch Notes" canonical: "https://docs.magma-maths.org/patchnotes/2.15-11.html" source: "https://docs.magma-maths.org/patchnotes/2.15-11.md" --- # Magma V2.15-11 Patch Notes ## Arithmetic Geometry - Fixed a regression in `ChabautyEquations`, which affected the results returned in the elliptic curve Chabauty routines in certain rare conditions. Reported and fixed by N. Bruin. ## Associative Arrays - A bug in assignment for associative arrays of aggregates has been fixed. Reported by N. Bruin. ## Coding Theory - Fixed a memory leak in the minimum weight computation for some quasi-cyclic codes. Reported by N. Aydin and M. Grassl. ## Commutative Algebra - A bug in [`Homogenization`](../CommutativeAlgebra/PolynomialRingIdealOperations/homogenization.md#function-homogenization-rngmpol-rngintelt-boolelt) has been fixed. Reported by M. Grassl. - A crash in computing random elements of a chain of univariate quotient rings has been fixed. Reported by M. Javadi. - A missing error check in `FieldOfFractions` for proper ideals of univariate polynomials has been inserted. Reported by B. Wardemann. - An incorrect result in `IsPrime` has been fixed. Reported by J. Kraemer. ## Congruence Subgroups - Fixed a bug in equivalence testing of cusps that would occasionally incorrectly decide that two equivalent cusps were inequivalent. Reported by R. Perlis. ## GaloisGroup - A couple of problems with leading coefficients in reducible polynomials has been fixed. Reported by A-S. Elsenhans. - A problem with linear factors in reducible polynomials has been fixed. Reported by A-S. Elsenhans. ## Groups - The code for `RandomProcess` with alternative supplied generators no longer tries to verify that the generators are in the group when the group is a permutation or matrix group. Response to complaint from E. O’Brien. - Two functions for converting small finitely presented groups to other types have been added. These are `PermutationGroup` and `PCGroup`. - The `IsTrivial` function for matrix groups over infinite fields has been fixed to use the fact that groups without generators are trivial. Bug reported by E. O’Brien. - A bug in `IsNilpotent` and `LowerCentralSeries` for matrix groups over infinite fields has been avoided by more error checking. Bug reported by E. O’Brien. - Generators for the special and general linear groups over the integers have been coded into Magma. Requested by E. O’Brien. - A bug in the filtering of subgroups when using the `Subgroups` family of functions with the `OrderEqual` or `OrderDividing` parameters set has been fixed. The bug led to classes of subgroups being missed. - User defined homomorphisms with domain a pc-group have been revised to allow preimage computations. Reported by D. Holt. ## Lattices - A bug in `IsIsometric` has been fixed. Reported by D. Kohel. ## Module Theory - A bug in [`Submodules`](../RepresentationTheory/ModulesOverAnAlgebraAndGroupRepresentations/submodule-lattice.md#function-repthy-submodules), when the number of submodules was overflowing a limit and causing and incorrect answer, has been fixed. Reported by E. O’Brien. ## Modules over Dedekind Domains - A matrix was inverted over the wrong ring potentially resulting in incorrect results in the intersection of two modules. This would only occur if the modules are created over a Magma-known Euclidean quadratic field. Reported by M. Sengun. ## Number Fields - An overzealous assertion in the code has been corrected. This problem could on rare occasions case an internal error while mapping elements into residue class fields. Reported by H. Nover. ## Quadratic Fields - Using Euclidean operations in [`QuadraticField(-3)`](../GlobalFields/QuadraticFields/creation.md#function-fldquad-quadraticfield) would result in the printing of several lines containing only 1. Bug reported by M. Sengun. - A crash in printing of orders of quadratic fields has been fixed. Bug reported by M. Sengun. ## Sequences - A bug in comparison of large sequences that use the range specifier has been fixed. Reported by J. Kimberley. ## Series Rings - Fixed the creation of an unramified extension by a polynomial not over the constant field.