---
title: "Magma V2.13-11 Patch Notes"
canonical: "https://docs.magma-maths.org/patchnotes/2.13-11.html"
source: "https://docs.magma-maths.org/patchnotes/2.13-11.md"
---

<a id="magma-v2-13-11-patch-notes"></a>
# Magma V2.13-11 Patch Notes

## Algebraic Geometry

- A bug in pullbacks by maps between curves has been fixed. Reported by B. Smith.
- Several redundant subset intrinsics have been removed. This fixes an ambiguous signature match when testing whether an indexed set of points is contained in a scheme. Reported by B. Smith.
- A bug in the parametrisation of rational plane curves has been fixed.
- A bug in `ShortBasis` for divisors on curves has been fixed. Reported by M. Grassl

## Algebras

- The action of a matrix on an element of a free algebra or quotient thereof now works properly. Bug reported by E. Rains.

## Coding Theory

- A bug that caused at most one cyclic generator matrix to be used during minimum weight computations has been fixed. Reported by M. Grassl.
- [`HasLinearGrayMapImage`](../CodingTheory/LinearCodesOverZ4/constructions.md#function-haslineargraymapimage-code) now works for the zero code. Bug reported by M. Villanueva.
- A bug that caused the results of [`GriesmerMinimumWeightBound`](../CodingTheory/LinearCodes/bound.md#function-griesmerminimumweightbound-fldfin-rngintelt-rngintelt) to be too high has been fixed. Reported by M. Kiermaier.

## Commutative Algebra

- The Hilbert polynomial/series functions have been speeded up. This affects several other functions, like `Degree` for projective schemes.

## Elliptic Curves

- The code for `IsDivisibleBy` or [`DivisionPoints`](../ArithmeticGeometry/EllipticCurves/point.md#function-divisionpoints-ptell-rngintelt) as applied to a point in the kernel of reduction of an elliptic curve over a p-adic field has been updated. There is now a much smaller loss in precision if all division points are required and some exist which do not reduce to 0.
- Point functions `IsWeaklyEqual` and `IsWeaklyZero` have been added. These test for weak equality/nullity of points over a variable precision p-adic field. Over an exact field, they are the usual equality/zero checks.

## Graded Rings

- A bug in the printing of graded rings has been fixed. Reported by B. Smith.

## Groups

- A bug in `IsConjugate` for two elements of a pc-group, when the elements are not contained in the conjugating group, has been fixed. An incorrect conjugating element was being returned.
- A bug computing image and kernel of a group homomorphism when the codomain is not a permutation or matrix group has been fixed. Reported by Eamonn O’Brien.
- A bug when computing `MaximalSubgroups` of Alt(49) has been fixed. Bug report from Colva Roney-Dougal, fix by Derek Holt.
- A crash when Subgroups is called on a PC-group with parameter `OrderEqual` set to a non-divisor of the group order has been fixed.

## Integers

- A bug that caused a crash when ECPP fails has been fixed.

## Lattices

- The function `IsIsometric` has been fixed so that it does not crash or return an incorrect answer when only a proper isometric embedding is found.

## Matrices

- The functions `Submatrix`, `Pfaffian` and [`Minor`](../MatricesLinearAlgebra/Matrices/properties.md#function-minor-mtrx-rngintelt-rngintelt) may now take index sequences specifying submatrices.

## Module Theory

- A bug in decomposition of algebras has been fixed. Reported by D. Gruenewald.

## Number Fields

- A bug in `NormEquation` over number fields that would, in certain trivial cases, trigger a runtime error, has been fixed.
- A bug in `Completion` of number fields that could in certain cases cause runtime errors has been fixed.

## Polynomial Rings

- A bug in multiplication in polynomial quotient rings over integer residue rings has been fixed. Reported by H. Hubrechts.
- A crash in the factorization of the polynomial 1 over function fields has been fixed. Reported by F. Hess.
- A coercion problem in `Evaluate` has been fixed. Reported by E. Rains.

## System

- Added a `%O` format code to the various printf-style directives and intrinsics. This enables a print level to be specified for the object. e.g., `printf "%O\n", X, "Minimal";`