--- title: "Magma V2.15-10 Patch Notes" canonical: "https://docs.magma-maths.org/patchnotes/2.15-10.html" source: "https://docs.magma-maths.org/patchnotes/2.15-10.md" --- # Magma V2.15-10 Patch Notes ## Elliptic Curves - Over GF(p), for a prime p of bit length less than 50, Magma now uses a fast internal BSGS for point counting rather than going through SEA. This is also used if the j-invariant of the curve lies in the base field and the characteristic is as above. - A bug in SEA has been fixed that caused (very rare) runtime errors in the processing of Elkies primes. ## Function Fields - Some bugs in the application of completion maps have been fixed. Reported by B. Wardemann. - A speedup in arithmetic has been achieved for sums of elements with denominators differing greatly in size. Problem reported by E. O’Brien. ## Galois Groups - A badly chosen prime was unneccessarily slowing down the computation of the roots of a polynomial with galois group An or Sn. ## Groups - The `IsNormal` command for fp-groups has been corrected to use the inverses of the group generators as well as the generators when conjugating, possibly correcting results for infinite groups. Bug reported by A. Previtali. - Filtering in the `Subgroups` command has been fixed, particularly for finding simple subgroups. Bug reported by J. Schmidt. - A bug in permutation groups, triggered when applying `IsConjugate` to a pair of sequences longer than the base length of the group, has been fixed. Bug reported by V. Gebhardt. - A crash when computing the kernel of a homomorphism with domain an infinite abelian group has been fixed. Bug reported by S. Siksek. - The constructions of the various projective orthogonal groups as permutation groups (functions [`PGO`](../FiniteGroups/PermutationGroups/linear-group.md#literal-literal-pgo-pgo-arguments), [`PSO`](../FiniteGroups/PermutationGroups/linear-group.md#literal-literal-pso-pso-arguments), [`POmega`](../FiniteGroups/PermutationGroups/linear-group.md#literal-literal-pomega-pomega-arguments), [`PGOPlus`](../FiniteGroups/PermutationGroups/linear-group.md#literal-literal-pgoplus-pgoplus-arguments), [`PSOPlus`](../FiniteGroups/PermutationGroups/linear-group.md#literal-literal-psoplus-psoplus-arguments), [`POmegaPlus`](../FiniteGroups/PermutationGroups/linear-group.md#literal-literal-pomegaplus-pomegaplus-arguments), [`PGOMinus`](../FiniteGroups/PermutationGroups/linear-group.md#literal-literal-pgominus-pgominus-arguments), [`PSOMinus`](../FiniteGroups/PermutationGroups/linear-group.md#literal-literal-psominus-psominus-arguments), [`POmegaMinus`](../FiniteGroups/PermutationGroups/linear-group.md#literal-literal-pomegaminus-pomegaminus-arguments)) have been adjusted so that all are subgroups of the corresponding PGO group. ## Hyperelliptic Curves - A bug occurring in CanonicalHeight} has been fixed. Reported by A. Brumer. ## Incidence Structures - A crash in [`BlockGroup`](../Combinatorics/Designs/automorphism-group.md#function-blockgroup-inc) of an incidence structure has been fixed. Bug reported by A. Munemasa. ## Local Fields - A bug in the creation of an arbitrary local field as an extension of a ramified extension which was an extension of an unramified extension has been fixed. ## Modules over Dedekind Domains - A problem involving zero-ideals was causing internal errors in `ElementaryDivisors`, reported by M. H. Sengun. ## Number Fields - A bug in accessing individual coefficients of number field elements using square brackets has been fixed. The bug could result in memory corruption. Reported by M. Grassl. - A bug in `CoprimeBasis` on trivial input would cause runtime errors because of untyped empty sequences. - A bug in `FixedField` when the group is trivial was fixed. - The creation of zero ideals via 0\*R where R is an order is now permitted. ## Quadratic Fields - A badly chosen square root in the conversion between ideals and quadratic fields would sometimes result in the conjugate ideal being used. - The subconstructor for orders of quadratic fields has been fixed to allow more general constructs. Reported by J. Voight.