---
title: "Magma V2.12-18 Patch Notes"
canonical: "https://docs.magma-maths.org/patchnotes/2.12-18.html"
source: "https://docs.magma-maths.org/patchnotes/2.12-18.md"
---

<a id="magma-v2-12-18-patch-notes"></a>
# Magma V2.12-18 Patch Notes

## Algebraically Closed Fields

- Bugs in [`AbsolutePolynomial`](../GlobalFields/AlgebraicallyClosedFields/absolute.md#function-absolutepolynomial-fldac) for ACFs with only one relation and in the function [`AbsoluteAffineAlgebra`](../GlobalFields/AlgebraicallyClosedFields/absolute.md#function-absoluteaffinealgebra-fldac) have been fixed. Reported by S. Murray.

## Commutative Algebra

- A very rarely occuring crash in the F4 algorithm over small prime finite fields has been fixed.
- A serious inefficiency in testing whether affine algebras are fields has been fixed. Reported by D. Schmidt.

## Elliptic Curves

- A typo has been fixed in the intrinsic `HasComplexMultiplication` so that it now behaves correctly for elliptic curves over $\mathbb{Q}$. Reported by Christian Wuthrich among others.

## Group Cohomology

- A bug that occurs when extending a soluble group by the trivial group has been fixed (function [`ExtensionsOfSolubleGroup`](../FiniteGroups/CohomologyAndExtensions/extensions-2.md#function-extensionsofsolublegroup-grpperm-grpperm)). Reported by K Andersen.

## Hyperelliptic Curves

- A bug in the point search for Jacobians of hyperelliptic curves that could cause random memory to be overwritten has been fixed.

## Infinities

- `Min` and `Max` now work on sequences consisting solely of infinite elements ($\pm$[`Infinity`](../BasicRings/Integers/infinity.md#function-infinity)`()`).

## Integer Factorisation

- Some leaks in the ECM code have been fixed.

## Lattices

- A bug when creating sublattices generated by a very large number of vectors has been fixed. Reported by A. Munemasa.

## Lie Theory

- The functions `WeightLattice` and `CoweightLattice` and functions which depend on these have been fixed to be in agreement with the documentation.
- Infinite recursion in [`CartanSubalgebra`](../LieTheory/LieAlgebras/sub.md#function-cartansubalgebra-alglie) for matrix lie algebras has been removed.

## Matrices

- A crash in `RationalReconstruction` for matrices has been fixed. Reported by M. Grassl.

## Matrix Algebras

- Error checks for left-ideal/right-ideal have been inserted for matrix algebras.

## Number Fields

- A change in the handling of requests for `Subfields` of degree greater than the field degree has introduced: instead of generating an error, the empty sequence is returned.
- In `NormEquation` for number fields, the handling of the internal precision was changed. This fixed a bug reported from Linz.
- A rare case of wrong deletion of elements of number fields has been fixed. This bug could only occur when non-simple and simple number fields were used simultaneously.
- A problem in the processing of the arguments of `Modinv` made the function inaccessible for order of quadratic fields, number fields and cyclotomic fields. As a result, this broke the ClassGroup fuction for quadratic forms.

## Permutation Groups

- A bug in evaluation of the class map for small permutation groups after intermediate calculations with the group has been fixed. Reported by J. Bray.

## Polynomial Rings

- A bug when calling Roots of an integral polynomial and a real field has been fixed. Reported by W. Bosma.
- A crash in multivariate factorization over $\mathbb{Z}$ has been fixed. Reported by M. Grassl.

## Representation Theory

- The function `GModule` taking a representation map has been fixed to respect the order of the group generators. Reported by D. Holt.