Magma V2.23-2 Patch Notes

Commutative Algebra¶

• A missing error in Variety for non-supported base rings has been added.
• Procedure SetGBGlobalModular has been added to set whether the global modular algorithm should be used when computing a Groebner basis over the rational field or a number field (while function GetGBGlobalModular gives the current value).

Elliptic Curves¶

• A bug with the SEA point-counting algorithm over finite fields defined by relative extensions was fixed.

Galois Groups¶

• Extra printing in Galois group computations has been cleaned up.
• A precision check in the computation of Galois groups of reducible polynomials over Q(t) has been fixed.

Graphs¶

• The automorphism group of a graph is now properly recomputed after labels are changed. This bug only affected V2.23-1.

Hadamard Matrices¶

• Traces is now the default algorithm for operations involving the canonical form or equivalency testing.
• The Hadamard database routines now explicitly set the canonical form algorithm to nauty for compatibility; this will be changed in a future patch release.

Hypergeometric Motives¶

• The HypergeometricTraceK intrinsic, applicable for non-Galois data and/or parameter specializations at non-rationals, has been improved and documented. Instigated by J. Voight.

Matrices¶

• The base algorithm for matrix echelonisation has been greatly improved in general for matrices of small to medium size with entries in GF$(p)$ for p=2,3,5,7. For example, matrix inversion over GF(2) in dimension up to 1000 is roughly 3 to 4 times faster on a typical Intel Core CPU.

Polynomial Rings¶

• A crash in multivariate resultant computation with a very large number of variables has been fixed.

System¶

• Using a very long undefined identifier no longer crashes.

p-Adics¶

• A bug with coercion of rational zeros into a p-adic field has been fixed. Such an p-adic number could be created, but would not be correctly be recognized as zero in comparisons.
• The PowerRelation intrinsic now ensures its output is monic, and there is some attempt to remove superfluous factors in it too.