---
title: "Magma V2.12-20 Patch Notes"
canonical: "https://docs.magma-maths.org/patchnotes/2.12-20.html"
source: "https://docs.magma-maths.org/patchnotes/2.12-20.md"
---

<a id="magma-v2-12-20-patch-notes"></a>
# Magma V2.12-20 Patch Notes

## Abelian Extensions of Number Fields

- A bug in `NormEquation` caused internal errors whenever the abelian extension was trivial. This has been fixed.
- In certain cases `NormEquation` would return elements rather than lists of elements. This has been fixed.

## Arithmetic Geometry

- A bug in counting points on genus 1 hyperelliptic curves has been fixed.
- Ambient spaces of dimension 0 have been allowed since they are used in `Chabauty`.

## Complex Fields

- Memory handling in [`Eisenstein`](../BasicRings/RealAndComplexFields/elliptic-modular.md#function-eisenstein-rngintelt-rngserelt) and related functions has been fixed.

## FP Lie algebras

- A missing error check for `NilpotentQuotient` has been inserted. The relations are also made monic.

## Function Fields

- Automorphisms for function fields now generates better error messages when the automorphisms of the base field cannot be computed.

## Groups

- A memory problem that occurred when constructing a homomorphism from a matrix group but with illegal images has been fixed. Bug reported by Markus Grassl.
- A memory problem within `SylowSubgroup` for permutation groups has been fixed.
- A problem with `RandomProcess` for permutation and matrix groups, where the `Generators` parameter may have been ignored, has been fixed.
- A bug in [`IdentifyAlmostSimpleGroup`](../FiniteGroups/DatabasesOfGroups/sgdb.md#function-identifyalmostsimplegroup-grpperm) for matrix groups has been fixed.

## Lattices

- A bug in `IsIsometric` has been fixed. Reported by M. Kirschmer.
- A bad error which caused lattice automorphism and isometry computations to run very slowly has been fixed. Reported by G. Nebe.
- A bug in [`OrthogonalDecomposition`](../LatticesQuadraticForms/Lattices/new-construction.md#function-orthogonaldecomposition-lat), which returned a decomposition of a proper sublattice, has been fixed. Reported by I. Middleton.

## Lie Theory

- The creation of Coxeter groups has been made more efficient.

## Number Fields

- A memory corruption problem in `IsIsomorphic` could result in incorrect results and internal errors. This has been fixed.
- The computation of Galois groups of constant polynomials would trigger an internal error and corrupt the memory. Constant polynomials have now been disallowed from `GaloisGroup`.
- A bug when using ext to extend a number field by a reducible polynomial has been fixed. Rather than triggering an internal error, the correct runtime error is now generated.
- `SUnitGroup` now returns a (usually) unassigned third result, so that regardless of the Raw parameter the result can be assigned to three variables.

## Polynomial Rings

- A hanging problem in factorization of polynomial rings over polynomial quotient rings has been fixed. Reported by D. Schmidt.

## Quadratic Fields

- `IsPrincipal` when applied to non-primitive ideals in quadratic fields would wrongly return an generator for the primitive part of the ideal rather than for the ideal. This has been fixed.
- In non-cyclic class groups of quadratic fields the discrete logarithm function could fail generating arbitrary errors, this has been fixed.

## Ring of Integers

- A crash in the ECM code while factoring a special class of integers has been fixed.
- A crash in the ECPP code while proving primality of a special class of integers has been fixed.