Magma V2.26-2 Patch Notes

Elliptic Curves¶

• A bug in the code for the intrinsic DualIsogeny 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 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 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 for a cone no longer includes the zero dual vector. This fixes a potential problem where IsInInterior could give the wrong answer. Note that this does not change the behaviour of MinimalInequalities which, as a minimal set of inequalities, never included zero.