---
title: "Magma V2.23-5 Patch Notes"
canonical: "https://docs.magma-maths.org/patchnotes/2.23-5.html"
source: "https://docs.magma-maths.org/patchnotes/2.23-5.md"
---

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# Magma V2.23-5 Patch Notes

## Arithmetic Geometry

- The function [`TwoCoverDescent`](../ArithmeticGeometry/HyperellipticCurves/two-selmer-set.md#function-twocoverdescent-crvhyp) has been improved. Also, a new parameter `Points` has been added, which can be set to a set of rational points on the curve, to be used for an early exit when the given points exhaust the upper bound for the Selmer set computed so far.
- The 3rd return value of the function `AutomorphismGroup` has been fixed for hyperelliptic curves.

## Coding Theory

- `MacWilliamsTransform` has been considerably sped up.

## Cyclotomic Fields

- A deletion problem with cyclotomic fields has been fixed. This was seen during computations with character tables and class groups.

## Galois Theory

- An internal problem with [`SolveByRadicals`](../GlobalFields/AlgebraicFunctionFields/galois.md#function-solvebyradicals-rngupolelt) has been fixed. Reported by M. Grassl.

## Group Theory

- Various improvements have been made to the large matrix group code.

## Hecke Characters

- Some problems with coercion of the trivial character were fixed, and the code now caches ideals to ensure compatability.

## Integers

- The upper limit on [`PrimesUpTo`](../BasicRings/Integers/prime.md#function-primesupto-rngintelt) has been changed so that a crash no longer ensues. Reported by M. Kirschmer.

## Lattices

- The crash involving [`BKZ`](../LatticesQuadraticForms/Lattices/reduction.md#function-bkz-mtrx-rngintelt) intrinsic over the rational field has been fixed.

## Polynomial Rings

- A crash in `Valuation` for univariate polynomials has been fixed. Reported by M. Stoll.
- New parameter `DegreeLimit:=D` added to `Factorization` for univariate polynomials so that only irreducible factors with degree at most the given bound $D$ are returned (this can lead to large speedups for certain base rings).  The general factorization algorithm for univariate polynomials over Z or Q has also been sped up. Requested by E. González-Jiménez.

## System

- The parent of an extended type is now the power structure of ECat, not the power structure of Cat.  Reported by T. Dokchitser.