---
title: "Magma V2.26-2 Patch Notes"
canonical: "https://docs.magma-maths.org/patchnotes/2.26-2.html"
source: "https://docs.magma-maths.org/patchnotes/2.26-2.md"
---

<a id="magma-v2-26-2-patch-notes"></a>
# Magma V2.26-2 Patch Notes

## Elliptic Curves

- A bug in the code for the intrinsic [`DualIsogeny`](../ArithmeticGeometry/EllipticCurves/morphism.md#function-dualisogeny-map) has been fixed by John Cremona. The bug was reported by Tony Scholl and an initial fix was provided by Tom Fisher.
- Code that sometimes led to stack overflow in intrinsic [`MordellWeilShaInformation`](../ArithmeticGeometry/EllipticCurvesOverQAndNumberFields/mordell-weil.md#function-mwsiref) has been revised to prevent this happening.  Reported by M. Voznyy.

## Groebner Bases

- An obscure crash in the dense F4 algorithm (arising in descent computations with elliptic curves) has been fixed. Reported by M. Voznyy.
- A crash in the symbolic phase of the F4 algorithm in the sparse monomial case has been fixed.  Reported by I. Ilmer.

## Modular Forms

- The function `eq` for modular form elements has been made consistent with `IsZero`.
- A slowdown in [`Newforms`](../ModularArithmeticGeometry/ModularForms/newforms.md#function-newforms-modfrm) for moderately-size cusp form spaces has been fixed.  Reported by A. Brumer.

## Number Fields

- A crash in the hom construction for orders of number fields has been fixed.  Reported by T. Keller.

## Representation Theory

- A crash in `AHom` for trivial action has been fixed.

## Sparse Matrices

- The function `ChangeRing` for sparse matrices now allows the map algorithm (as for dense matrices).  Issue reported by J. Gibson.

## Toric Varieties

- [`Inequalities`](../Geometry/Polytopes/basic-combinatorics.md#function-inequalities-torcon) for a cone no longer includes the zero dual vector. This fixes a potential problem where [`IsInInterior`](../Geometry/Polytopes/combinatorics.md#function-isininterior-torlatelt-torcon) could give the wrong answer. Note that this does not change the behaviour of [`MinimalInequalities`](../Geometry/Polytopes/basic-combinatorics.md#function-minimalinequalities-torcon) which, as a minimal set of inequalities, never included zero.