Magma V2.14-12 Patch Notes

Algebraic Curves¶

• Some bugs have been fixed in the Divisor intrinsics giving the divisor corresponding to a zero-dimensional subscheme of a curve.

Algebraic Function Fields¶

• The completion mapping for the field defined by $y = 0$ has been fixed.
• DecompositionType for places of the rational function field has been fixed.

Coding Theory¶

• AutomorphismGroup for additive codes now returns a more helpful error message when the code is not defined over $GF(4)$. Reported by M. Grassl.

Documentation - Handbook¶

• A new, corrected version of the Handbook has been compiled.

Elliptic Curves¶

• A crash in point division has been fixed. Reported by R. Conceicao.
• A bug in the computation of twists of supersingular elliptic curves in characteristics 2 and 3 has been fixed. Reported by J. Cremona.

Galois Groups¶

• The computation of Galois groups of polynomials over $\mathbb{Q}(t)$ (rational function field over the field of rational numbers) has been completely rewritten. As a result, a number of outstanding bugs with wrong results have been fixed, but there is a significant slowdown on some examples. Bugs reported by Kurt Foster and Martin Hintermeier.
• A few minor problems when using invariants over complicated rings has been fixed. Without the fix, certain computations over $\mathbb{Q}(t)$ could cause internal errors.
• A bug in the computation of the number of multipliactions in an invariant has been fixed. Without the fix, the function could enter an infinite recursion and terminate Magma.
• A bug in the computation of a bound for the values of the "ProdSum" invariant has been fixed. In certain examples, the wrong bound (too small in general) could have caused wrong results.

Groups¶

• A bug in finitely presented groups has been fixed. Bug reported by Jack Button.
• A bug in Subgroups function, when restricted to elementary abelian subgroups, has been fixed. Bug reported by Markus Grassl.
• A bug when constructing a sequence of rewrite system groups has been fixed. Bug reported by Jack Schmidt.
• A bug when evaluating an empty sequence of words using Evaluate has been fixed. Bug reported by Henrik Baarnhielm.
• The function CompositionSeries for a permutation group has been upgraded and corrected to give a full composition series for the group, rather than stopping at the soluble residual.

Hyperelliptic Curves¶

• A bug in the creation of places on hyperelliptic curves has been fixed.

Matrices¶

• A slow down in matrix multiplication over the rationals has been fixed. Reported by B. Ricard.

Number Fields¶

• A bug in the computation of conjugates of orders in relative extensions has been fixed. The old code would cause a runtime error.

Orders of Associative Algebras¶

• Creation of ideals by multiplication of an order and an element has been fixed.
• Equality of orders has been fixed.
• Some bugs in some operations with orders and their elements have been removed.

Real Fields¶

• BesselFunction has been fixed.