--- title: "Magma V2.18-5 Patch Notes" canonical: "https://docs.magma-maths.org/patchnotes/2.18-5.html" source: "https://docs.magma-maths.org/patchnotes/2.18-5.md" --- # Magma V2.18-5 Patch Notes ## Algebraic Geometry - A trivial problem (resulting in runtime errors) in equality testing for resolution graphs has been fixed. Reported by C. Gorzel. ## Associative Arrays - The operator `#` now works for associative arrays (returning the number of keys). ## Coding Theory - A bug in [`ParityCheckMatrix`](../CodingTheory/AdditiveCodes/access.md#function-paritycheckmatrix-code) has been fixed; this bug could cause the parent of the returned matrix to have the wrong number of rows when the code was defined over $Z_4$. Reported by M. Grassl. ## Commutative Algebra - Some crashes in `PrimaryDecomposition` when weights are present have been fixed. Reported by S. Jambor. - A crash in `Variety` over real fields has been fixed. ## Elliptic Curves - A bug in [`TatePairing`](../ArithmeticGeometry/EllipticCurvesOverFiniteFields/pairings.md#function-tatepairing-ptell-ptell-rngintelt) and [`ReducedTatePairing`](../ArithmeticGeometry/EllipticCurvesOverFiniteFields/pairings.md#function-reducedtatepairing-ptell-ptell-rngintelt) has been fixed. This was producing wrong results for the pairing of P and Q when P=Q is of order two. Reported by B. Allombert. - Saving a workspace when the elliptic curve database is around no longer causes the database to return read errors thereafter. - The elliptic curve database has been updated to conductor 229,999. - A bug with [`ManinConstant`](../ArithmeticGeometry/EllipticCurvesOverQAndNumberFields/intro-2.md#function-maninconstant-crvell-fldrat) of 27a4 and 80b4 was fixed. Reported via the Sage bug tracking system. - `MinimalModel` was accidentally disabled for non-totally real fields; it is now restored to normal. Reported by E. Gonzalez-Jimenez. ## Function Fields - A fix has been made to the bounds used in [`GaloisSubgroup`](../GlobalFields/GaloisGroupsAndAutomorphisms/galois.md#function-galoissubgroup-fldnum-grpperm) and [`GaloisQuotient`](../GlobalFields/GaloisGroupsAndAutomorphisms/galois.md#function-galoisquotient-fldnum-grpperm) in characteristic p and to bounds used for reducible polynomials. - Improvements have been made to `MaximalOrder` computations in Artin–Schreier extensions. The use of a special algorithm for these extensions has been limited to function fields whose constant field is perfect. ## Groups - A crash when computing the `AbelianQuotient` of a permutation group has been fixed. - A bug in the `IsTransitive` filter for the `Subgroups` command, which, for larger groups, caused the whole group to be missed, has been fixed. Reported by G. Royle and by D. Holt. - The [`ClassicalMaximals`](../FiniteGroups/AlmostSimpleGroups/properties-lie-groups.md#function-classicalmaximals-monstgelt-rngintelt-rngintelt) routine has been fixed in the cases of $Sp(12, 3)$, $O_+(10,q)$ and $O_-(10,q)$, where there were errors in the subgroups returned. Fixed by D. Holt, who noticed the errors. - The [`LowIndexNormalSubgroups`](../FinitelyPresentedGroups/FPGroups/subgroup-fin-index.md#function-lowindexnormalsubgroups-grpfp-rngintelt) routine has been given an improved method of computing maximal submodules of an elementary abelian section, following comments by M. Conder. - A bug in `LowIndexSubgroups` for permutation groups has been fixed. Reported by A-S. Elsenhans. - A crash in matrix groups that showed up as a crash in `Subgroups` has been fixed. - A new permutation group intrinsic [`pCoreQuotient`](../FiniteGroups/PermutationGroups/characteristic-subgroup-normal-structure.md#function-pcorequotient-grpperm-rngintelt) has been added at the request of D. Holt. - A crash when computing the automorphism group of a matrix with trivial automorphism group has been fixed. Reportd by M. Grassl. ## Hyperelliptic Curves - A bug in [`TwoCoverDescent`](../ArithmeticGeometry/HyperellipticCurves/two-selmer-set.md#function-twocoverdescent-crvhyp) involving excessively high levels of precision in p-adic fields has been fixed. This was preventing the algorithm from terminating in some cases. Reported by E. Gonzalez-Jimenez. ## Integers - A crash when calling [`Binomial`](../BasicRings/Integers/combinatorics.md#function-binomial-rngintelt-rngintelt) or [`NumberOfPermutations`](../Combinatorics/EnumerativeCombinatorics/combinatorics.md#function-numberofpermutations-rngintelt-rngintelt) on large integers has been fixed. ## Lie Theory - The intrinsic `IsSimple` for Lie algebras has been fixed to return [`false`](../MagmaLanguage/StatementsAndExpressions/boolean.md#literal-literal-false-false) for Lie algebras of dimension 1. Reported by R. Zeier. - A crash in the package for Lie algebras generated by extremal elements has been fixed. ## Number Fields - Null sequences are now handled in `PseudoMatrix` given a sequence and a matrix. ## Quadratic Fields - A crash when the map from the class group is reconstructed and applied has been fixed. Reported by M. Kirschmer. ## Quaternion Algebras - Trivial errors in implementation of the mass formula have been corrected. (This caused bugs in enumerating left or right ideal classes.) Reported by D. Smertnig. ## Rationals - An obscure bug in rational subtraction has been fixed. Reported by E. Thomé. ## System - A bug has been fixed that could cause crashes when using [`eval`](../MagmaLanguage/StatementsAndExpressions/eval-expression.md#literal-literal-eval-eval-expression) with a database around.