--- title: "Magma V2.18-2 Patch Notes" canonical: "https://docs.magma-maths.org/patchnotes/2.18-2.html" source: "https://docs.magma-maths.org/patchnotes/2.18-2.md" --- # Magma V2.18-2 Patch Notes ## Algebraic Function Fields - The arithmetic of elements in different fields of fractions of orders has been fixed. - The computation of a maximal order in an Artin-Schreier extension has been improved. ## Algebraic Number Fields - Fixes have been made to `Subfields` of extensions of Q. Reported by J. Klüners. ## Commutative Algebra - A crash in `FreeResolution` for modules over number fields has been fixed. Reported by H. Campbell. ## Elliptic Curves - The database of elliptic curves over $\mathbb{Q}$ of small conductor, constructed by John Cremona, has been updated to include curves representing all isogeny classes for all conductors less than 210000. ## Global Arithmetic Fields - A check for fields defined by a sequence of polynomials has been added to `Subfields`. Reported by J. Voight. - A fix has been made to `meet` for an order with a field. - A fix has been made to `GaloisGroup` computations. Reported by J. Klüners. ## Group Algebras - A crash when computing `RegularRepresentation` of a group algebra over a multivariable polynomial ring has been trapped to give a runtime error instead. The algorithm is only implemented for base rings that are fields or Euclidean domains. Reported by S. Humphries. ## Matrix Groups - A bug in the machinery for recognising classical groups, which caused a proper subgroup of $Ømega(3, 7^2)$ to be incorrectly identified as the full group, has been fixed. - A bug in the machinery for performing Aschbacher analysis on a matrix group over a finite field, whereby a group of order 16 in $GL(3, 7^2)$ was not identified as a subgroup of the normaliser of an extraspecial group, has been fixed. ## Representation Theory - A crash in `AbsolutelyIrreducibleModules` over a field of characteristic 0 has been fixed. Reported by E. O’Brien. ## Series Rings - `ChangeExponentDenominator` on a series has been fixed to ensure that the resulting series is normalized. ## p-Groups - A revised version of the intrinsic [`ClassTwo`](../FiniteGroups/FiniteSolubleGroups/p-groups.md#function-classtwo-rngintelt-rngintelt), which counts the set of p-class 2 d-generator groups, prepared by Michael Vaughan-Lee, exploits types of matrices to greatly reduce the cputime.