--- title: "Magma V2.21-5 Patch Notes" canonical: "https://docs.magma-maths.org/patchnotes/2.21-5.html" source: "https://docs.magma-maths.org/patchnotes/2.21-5.md" --- # Magma V2.21-5 Patch Notes ## Algebraic Number Fields - An iterator has been provided to iterate through elements of quotients of orders of relative number fields by their ideals. Reported by M. Kirschmer. - It is now possible to construct `Random` elements of quotients of orders of relative number fields by their ideals. - Compatibility has been improved for orders of number fields. This allows the comparison of orders having the same coefficient ring using `eq`. Reported by M. Kirschmer. ## Commutative Algebra - A problem in comparison of module elements has been fixed. Reported by C. Quitte. ## Dirichlet Characters - A problem with assigning names to a Dirichlet group generators was fixed. ## Elliptic Curves - The [`MinimalQuadraticTwist`](../ArithmeticGeometry/EllipticCurves/creation.md#function-minimalquadratictwist-crvell) intrinsic when applied to a rational whose numerator has a prime-power divisor $p^e$ with $6|e$ and $p>3$ congruent to 3 mod 4 could return a curve with a different $j$-invariant. Reported by A. Sutherland. ## Groups - A bug in `Subgroups` when using `IndexEqual` set to an impossible index has been fixed. Reported by A. Sutherland. - A crash using the transversal map with groups of type GrpFPCox has been fixed. Reported by B. Howlett. - If explicitly setting all of the conjugacy classes of a group, they are no longer re-ordered if they are already sorted. Previously, elements with the same order and length could be re-ordered in this case. Reported by S. Goldstein. - A crash when computing preimages with a [`BlocksAction`](../FiniteGroups/PermutationGroups/actions.md#function-blocksaction-grpperm-any) map has been fixed. Bug reported by Juergen Klueners. ## Lattices - Using the `Max` parameter with `ShortestVectors` could lead to incorrect caching of partial information, and give erroneous results for later enumerations. Reported by C. Doberstein. ## Series Rings - The `IsSquare` intrinsic for series over the rationals whose constant coefficient (after removing the valuation) was not 1 could give wrong answers due to `Log`/`Exp` not working. The same problem can also occur with `IsPower` more generally. Reported by M. Stoll. - `Roots`, to a given precision, of polynomials over series rings over inexact rings have been disallowed.