Magma V2.22-7 Patch Notes

Algebraic Number Fields¶

• Divisors of elements of orders of algebraic number fields now gives an error when presented with an input of zero. Reported by M. Cuntz.

Artin Representations¶

• A precision-based bug when computing local data at bad primes was fixed.

Binary Quadratic Forms¶

• The Distance intrinsic on a single form has been removed.
• Reduction now does not compute or return the transformation matrix if the results are being printed or only the first return value is used.
• Reduction has been sped up.
• A bug has been fixed in IsEquivalent that could have caused the resulting transformation matrix to not be correct.
• IsEquivalent now allows returning transformation matrices in the real case. If non-narrow equivalence has been asked for, then the resulting transformation may produce the complementary form <-a, b, -c>.
• IsEquivalent has been sped up.

Elliptic Curves¶

• The Cremona database of elliptic curves of small conductor has been updated to conductor 399,999.
• A problem with AnalyticRank for elliptic curves over number fields with even degree was fixed. Reported by D. Lorenzini.
• A problem with EulerFactor for elliptic curves over number fields with nontrivially intersecting ramification was fixed. This also appeared in EulerFactor for an elliptic curve twisted by an Artin representation, giving a result in a cyclotomic field rather than a complex field. Reported by D. Lorenzini.

Galois Groups¶

• Some improvements have been made to the computation of Galois groups.
• A bug in SolveByRadicals for non-monic polynomials has been fixed. Reported by P. Lisonek and fixed by Stephan Elsenhans.
• The intrinsic GaloisSplittingField now applies to polynomials over number fields. This used to be the case but was removed probably by error for a time. Reported by J. Sijsling.
• A bug involving Galois groups over function fields was fixed. Reported by B. Naskrecki.

Groups¶

• Some missing checks have been added to prevent creating matrix groups over inexact rings such as the real numbers.
• An infinite loop which can arise when computing normalizers and the trivial subgroup of a pc-group has been fixed. Bug reported by T. Dokchitser.

Hyperelliptic Curves¶

• RichelotIsogenousSurfaces has been patched, in particular for cases where the same codomain was listed 3 times rather than 3 different ones.

Hypergeometric Motives¶

• A problem with the computation of the conductor in the identification of the Grossencharacter of a Jacobi motive over Q(zeta_4) was fixed.

L-series¶

• A bug with the TateTwist of a Grossencharacter with nontrivial Dirichlet component has been fixed.

Lattices¶

• Bugs arising from computing Coordinates for vectors in lattices over a real field have been fixed.

Laurent Series Rings¶

• The hom constructor is now supported for Laurent series rings.

Local Fields¶

• A possible crash when powering by large exponents has been fixed.
• A crash involving HenselLift was changed to give a runtime error.

Matrix Groups¶

• IrreducibleSubgroups has been updated to include the insoluble irreducible subgroups of degree 3; the code was prepared by Barry Hurley. This generalises and replaces the function IrreducibleSolubleSubgroups.
• This patch release includes a new version of the CompositionTree package which contains more efficient versions of the ClassicalRewriting intrinsics (Csaba Schneider) and the RecogniseSmallDegree intrinsic (Eamonn O'Brien).
• A crash in the intrinsic SuzukiConjugacyClasses has been fixed by Henrik Baarnhielm.
• A crash in IsAbsolutelyIrreducible has been fixed.

Polynomials¶

• The SmallRoots intrinsic no longer crashes when X is 0.

Real Numbers¶

• ExponentialIntegral now accepts negative arguments.
• ExponentialIntegral, LogIntegral, and DawsonIntegral should be slightly more accurate in some cases.

Rings¶

• The functions IsFinite and # for rings now give a proper error message if an algorithm is not available (instead of sometimes returning false). Issue reported by S. Szabo.

Schemes¶

• A bug in Reduction for schemes has been fixed. Reported by S. Vishkautsan.

Symmetric Functions¶

• Coercion of symmetric functions into suitable polynomials rings has been made more flexible. Reported by T. Coates.