Magma V2.22-4 Patch Notes

Algebraic Function Fields¶

• The algorithm choice for computing a 2-element representation of an ideal has been improved. Reported by R. Granger.

Coding Theory¶

• The function ExtendCode has been restored (accidentally only available as ExtendCodeField previously). Issue reported by D.W.C. Kuijsters.

Commutative Algebra¶

• Some operations with of fields of fractions of affine algebras have been sped up. Related crash (now fixed) reported by T. Ikuta.
• A bug in factoring polynomials over polynomial quotient rings over finite fields (which are themselves finite fields) has been fixed. Reported by A. Sutherland.
• A problem with linear factors in reducible polynomials has been fixed. Reported by A-S. Elsenhans.
• Crashes in Groebner basis computation over the rational field has been fixed. Reported by A-S. Elsenhans.

Cubic models of curves¶

• A crash with PointSearch for cubic models has been fixed.

Dedekind Modules¶

• A crash involving Dedekind modules has been fixed. Reported by V. Kliuchnikov.
• A crash when constructing a Dedekind module of degree 0 has been fixed. Reported by M. Kirschmer.

Finite Fields¶

• A crash when trying to compute a logarithm in a large finite field for which the data is not available has been fixed. Reported by M. Tillinghast.

Graphs¶

• Using 'in' to test whether a set or sequence of vertices is in the edge set of a graph now returns false instead of raising an error when there is no corresponding edge.

Group Characters¶

• A crash in the group characters code has been fixed. Bug report from Matthieu Rambaud.
• The intrinsic Basis when applied to a character ring now uses the default CharacterTable algorithm, instead of always going to the Dixon-Schneider algorithm.

Groups¶

• Calls to the ASp functions now trap odd dimensions to give a runtime error. Bug reported by T. Dokchitser.
• A crash when computing projective classical groups over a large finite field has been fixed. Bug reported by T. Dokchitser.
• Incorrect construction of some low dimensional PGO groups fixed. Bug reported by T. Dokchitser.
• Dimension lower bounds on the Spin, SpinPlus and SpinMinus intrinsics are all now 4. This fixes a crash reported by T. Dokchitser.
• The order assigned to PSigmaU(2,q), when q = 3 mod 4, has been corrected. Bug reported by T. Dokchitser.
• An improved access function for a single SmallGroup of order p^7 (p >= 7) is included. Request of E. O'Brien.

Hyperelliptic curves¶

• A longstanding bug with point counts on genus 1 hyperelliptic curves has been fixed (the twisting parameter was applied twice). Reported by E. Howe.

Lattices¶

• A crash with BKZ when the number of columns exceeded the rank was fixed. Reported by A.-S. Elsenhans.

Matrix Algebras¶

• A bug involving the wrong element type when iterating over a matrix lie algebra has been fixed. Reported by J. Maglione.

Numerical Linear Algebra¶

• A problem with images of complex matrices was fixed.

Sparse Matrices¶

• A missing error check has been added to Nullspace applied to sparse matrices over rings which are not supported. Reported by D. Yasaki.