---
title: "Magma V2.21-11 Patch Notes"
canonical: "https://docs.magma-maths.org/patchnotes/2.21-11.html"
source: "https://docs.magma-maths.org/patchnotes/2.21-11.md"
---

<a id="magma-v2-21-11-patch-notes"></a>
# Magma V2.21-11 Patch Notes

## Commutative Algebra

- A crash in Groebner basis computation of algebraic number fields of degree 1 has been fixed.

## Elliptic Curve Pairings

- A problem with [`ReducedTatePairing`](../ArithmeticGeometry/EllipticCurvesOverFiniteFields/pairings.md#function-reducedtatepairing-ptell-ptell-rngintelt) has been fixed. Reported by B. Allombert.

## Elliptic Curves

- An incorrect answer with `Order` of a torsion point over a number field has been fixed. The error was that the p-power torsion was not being bounded correctly in some cases. Reported by E. Gonzalez Jimenez.

## Function Fields

- The application of the `Completion` mapping and use of `Expand` have been fixed for non-simple relative extensions.
- `UnderlyingRing` can now be applied to extensions of infinite degree.
- The [`CoveringStructure`](../MagmaLanguage/StatementsAndExpressions/type.md#function-coveringstructure-str-str) of two sets of places is now a group of divisors which all places in those sets can be coerced into.
- `Automorphisms` has been fixed for non-simple extensions.
- A crash involving factorization of a chain of function fields (coming from `BaseChange` for hyperelliptic curves) has been fixed.  Reported by M. Stoll.

## Groups

- An error in applying `CayleyGraph` to a group of type `GrpFP` has been fixed. Bug reported by Miles Reid.
- Incorrect printing of certain values in character tables has been fixed. The bug afflicted printing of non-integer values in a cyclotomic field of degree 2, where the magnitude of the coefficients exceeded $2^{30}$. Printing of individual characters and character values was not in error. Bug reported by Eamonn O’Brien.

## Lattices

- The `InnerProductMatrix` of a lattice over a real field is now of the correct degree.
- `AutomorphismsGroup` has been fixed when Bacher polynomials are used.
- [`ClosestVectors`](../LatticesQuadraticForms/Lattices/enumeration.md#function-closestvectors-lat-modtuprngelt) has been fixed in a case where the inner product matrix has large entries.
- [`BKZ`](../LatticesQuadraticForms/Lattices/reduction.md#function-bkz-mtrx-rngintelt) now works for matrices whose rows are dependent. Reported by M. Kudo.

## Lie Theory

- A crash caused by incorrect input to [`LieRepresentationDecomposition`](../LieTheory/RepresentationsOfLieGroupsAndAlgebras/representations-constructing.md#function-lierepresentationdecomposition-rootdtm) has been fixed. The crash has become a runtime error. Bug reported by Markus Grassl.

## Number Fields

- Internal errors with the message “assertion order_basis_real_inv(ord) failed” can no longer occur.  (This occurred where a lower bound is obtained on the eigenvalues of a real matrix.  Now, appropriate precision is used for this; previously, no attempt was made to do so.  This likely meant that the bound obtained was sometimes garbage; it is not known whether this was likely to cause incorrect results to be returned to the user.)
- A major problem (existing for several years) has been fixed, where calls to `Completion` or `LocalRing` would corrupt existing local rings. Reported by M.~Stoll.
- A segfault which could occur during calls to various routines has been fixed. Reported by M.~Stoll.
- Significant improvements have been made to conic solving.  (As a consequence, descent methods are now effective for certain elliptic curves.)
- The [`CoveringStructure`](../MagmaLanguage/StatementsAndExpressions/type.md#function-coveringstructure-str-str) of two sets of places is now a group of divisors which all places in those sets can be coerced into.
- `ChineseRemainderTheorem` taking an ideal, a sequence of infinite places, an element and a sequence of signs has been fixed when the element given is in the ideal. Reported by M. Kirschmer.