--- title: "Magma V2.29-8 Patch Notes" canonical: "https://docs.magma-maths.org/patchnotes/2.29-8.html" source: "https://docs.magma-maths.org/patchnotes/2.29-8.md" --- # Magma V2.29-8 Patch Notes ## Aggregates - Printing of multisets now respects the print level properly for elements with multiplicity greater than 1. Reported by Markus Grassl. ## Algebraic Curves - `RandomGenus5CurveNonTrigonal` hung forever over fields of characteristic 2. It now reports a clear error instead. - [`GonalityPreservingLift`](../AlgebraicGeometry/AlgebraicCurves/function_field.md#function-gonalitypreservinglift-crv-fldfun) on a non-trigonal genus-5 curve over a field of characteristic 2 used to fail with an internal “Division by zero”. It now reports a clear characteristic-2 error. ## Algebraic Function Fields - A crash when constructing an ideal of an order of an algebraic function field using a sequence containing one zero has been fixed. Reported by Florian Hess. - Print names are now automatically assigned to the algebraic function field constructed to be a rational function field if the rational function field has print names assigned. Reported by Florian Hess. - Coercion into algebraic function fields has been extended/improved so that evaluation of polynomials at elements of such fields (with automatic coercion) now behaves correctly. Reported by Shiva Chidambaram. ## Algebraic Number Fields - The efficiency of memory management has been improved when deleting many number fields. Reported by Andrew Sutherland. - Embedding information is now reliably retained between fields and subfields constructed from them. ## Algebraic Surfaces - The `BettiNumber` intrinsic for elliptic surfaces over a non-rational base curve now uses the correct genus contributions. - We improved [`ParametrizeDelPezzo`](../AlgebraicGeometry/AlgebraicSurfaces/srfcs-P3.md#function-as-prmdp) for smooth degree-5 surfaces by trying all 5 choices of removal quadric in the pair-of-points construction. ## Algebras - A bug in `sub<>` for non-associative algebras, where products of basis elements were not included, has been fixed. Reported by Justin McIlroy. - Signature matching and dispatch has been fixed so that multiplication of a polynomials defined over an algebra and a scalar in the algebra now behaves correctly. Reported by Przemyslaw Koprowsk. - A crash arising from incorrect memory handling in the function [`UniversalEnvelopingAlgebra`](../LieTheory/LieAlgebras/universal_enveloping_algebras.md#function-universalenvelopingalgebra-alglie) has been fixed. ## Automatic Groups - New function `IsConjugate` to test conjugacy for infinite-order elements of a hyperbolic group. ## Basic Algebras - The algorithm to compute a basic algebra from a presentation has been significantly improved by the use of sparse matrices; this can also save memory. Reported by David Benson. ## Coding Theory - Fixed a race condition in the threaded `WeightDistribution` algorithm. ## Commutative Algebra - Unexpected behaviour in the [`Homogenization`](../CommutativeAlgebra/PolynomialRingIdealOperations/homogenization.md#function-homogenization-rngmpol-rngintelt-boolelt) function for multivariate polynomials ideals has been fixed. Reported by Daniele Taufer. - A crash when computing homogeneous Groebner bases has been fixed. Reported by Sachi Hashimoto. - A bug where `PrimaryDecomposition` could create ideals which did not have properly reduced Groebner bases has been fixed. - A hang in `Radical` testing for ideals with many variables in small characteristic has been fixed. Reported by Steve Huang. - The FGLM algorithm now selects most monomial orders for the target order (when the `Al := "FGLM"` parameter is given). Requested by Eric Rains. - New function `NumberField(A)` for affine algebra A (in the case that A is a field) has been added. Requested by Eric Rains. ## Finite Groups - Added intrinsic [`IdentifyGroupBySearch(G)`](../FiniteGroups/DatabasesOfGroups/smlgps-database.md#function-grpdata-identifygroupbysearch), which returns the `<#G, k>` label of G in the small groups database by iterating the database with cheap invariants (derived subgroup order, exponent, centre order, etc.) followed by an IsIsomorphic check. This is a fallback for orders such as 1152 and 1536 for which CanIdentifyGroup returns false. The error raised by IdentifyGroup on such orders now mentions this fallback. Reported by Dan Yasaki. - Functions like `CosetAction` for matrix groups defined over quotient rings of orders of number fields are now properly supported. Reported by Steve Huang. - A small bug in maximal subgroups for Sp(8,4) has been fixed. Reported by Tim Burness. - New function `WordInGenerators` which uses an algorithm of Minkwitz to try to write elements of a finite permutation or matrix group as a reasonably short word in the user generators. ## Finitely Presented Groups - Fixed a crash in [`IsAutomaticGroup`](../FinitelyPresentedGroups/AutomaticAndHyperbolicGroups/automatic-groups.md#function-isautomaticgroup-grpfp) and `AutomaticGroup` that could abort Magma when the system temporary directory path was long. ## Invariant Rings - A hang in `PrimaryInvariants` for diagonal matrix groups has been fixed. Reported by David Benson. ## Lattices - A crash in `IsIsometric` for integral lattices has been fixed. Reported by Jeremy Rouse. ## Local Fields - Precision when constructing `Eltseq` of an element in a ramified extension has been improved. Reported by Kevin Keating. - Precision when coercing an element sequence into a local field has been improved. Reported by Kevin Keating. ## Matrices - Fixed a precision bug in numerical complex linear algebra (`Solution`, `Kernel`, `Rank`) where an internal random-unitary generator was passed the wrong parent and used a heap-state-dependent precision, causing results to vary in the last bits across sessions. - The algorithms to compute the echelon form or nullspace of a matrix defined over the quotient of a maximal order of a number field by any ideal is now supported properly for the first time. Reported by Dan Yasaki. - A crash in `Determinant` for matrices defined over quaternion algebras has been fixed. Reported by Lewis Combes. ## Matrix Groups - Algorithms for matrix groups defined over quaternion algebras are now supported properly. Reported by Markus Grassl. ## Modular Curves - Implemented faster version of [`X0NQuotient`](../ModularArithmeticGeometry/ModularCurves/mod-crv-quotient.md#function-x0nquotient-rngintelt-rngintelt) when the quotient is an elliptic curve embedded in a high dimensional space. Reported by Oana Padurariu. ## Permutation Groups - New function [`TwoClosure`](../FiniteGroups/PermutationGroups/actions.md#function-twoclosure-grpperm) to compute the two-closure of a transitive permutation group. ## Quadratic Fields - The `Conductor` of some quadratic orders has been fixed to match the documentation and equivalent computations. Reported by Anthony Henderson. ## Representation Theory - A bug in `Complement(M, S)` for G-modules M,S (where the base ring was not a finite field, the integer ring or the rational field) has been fixed. Reported by Justin McIlroy. ## System - The command-line usage and documentation now describe all user-facing startup options, and -h, -? and –help now display the usage message and exit successfully. - Blank lines are now preserved in strings even when reading from standard input (in particular when in a terminal). - A fix has been made so infinite recursion (causing a crash) in traceback printing on errors is now avoided. - A fix in traceback printing has been made so that whenever an error occurs while printing a function argument, the argument is abbreviated and the original error message is now clearly printed properly. Reported by David Roe.