---
title: "Magma V2.13-8 Patch Notes"
canonical: "https://docs.magma-maths.org/patchnotes/2.13-8.html"
source: "https://docs.magma-maths.org/patchnotes/2.13-8.md"
---

<a id="magma-v2-13-8-patch-notes"></a>
# Magma V2.13-8 Patch Notes

## Arithmetic Geometry

- Some bugs in the characteristic two canonical lift code for point-counting on hyperelliptic curves/Jacobians have been fixed.

## Elliptic Curves

- In `TwoSelmerGroup` for curves over number fields, some further precision problems have now been handled.

## Finite Fields

- A bug in `IsPower``(a, n)` for large values of n over large fields has been fixed. Arbitrarily large n is now supported for the first time. Bug reported by Eamonn O’Brien.

## Galois Groups

- A bug in the Galois group package that would occasionally introduce an infinite loop using more and more memory has been fixed.

## Groups

- Two functions called `Transversal` have been added for the class of finite finitely-presented Coxeter groups. These give minimal length right- and double-coset representatives for standard parabolic subgroups (specified by a set of integers). Algorithms supplied by Bob Howlett.
- For matrix groups, a bug in the implementation of the Murray-O’Brien base point selection method has been fixed. Bug reported by Eamonn O’Brien.
- A bug in the recognition of non-generic orthogonal plus matrix groups over finite fields has been fixed. Bug reported by Mark Stather.

## Module Theory

- A bug in the [`Meataxe`](../RepresentationTheory/ModulesOverAnAlgebraAndGroupRepresentations/structure.md#function-modalg-meataxe) algorithm in rare cases involving the endomorphism ring has been fixed (the bug was only in V2.13).

## Number Fields

- Generators of a fractional ideal in non-maximal order would return an inconsistent eltseq. This has been fixed.
- Decomposition of elements of field of fractions of non-maximal orders would cause an internal error to be triggered. The decomposition of such elements (into prime ideals) has been disabled as it is in general not unique.

## Polynomials

- A bug in polynomial factorization over integers, where a reducible polynomial was very occasionally considered irreducible, has been fixed.