Change log for Magma V2.12-21 (Released 20/4/2006)

Algebraic Geometry

·A bug in ProjectiveClosure has been fixed. This occasionally produced the wrong result when the affine argument had a super-scheme distinct from an ambient.

·A bug in the coercion of elements into a function field of a scheme has been fixed.

Arithmetic Geometry

·A bug in conic parametrisation was fixed. This had caused four descent to return spurious answers for the elliptic curve y2 = x3 + 1026x. Reported by Joerg Jahnel.

·CanonicalHeight for points on Jacobians was patched.

Finite Fields

·A bug in discrete logarithms in fields of characteristic two has been fixed.

Local Rings and Fields

·A memory leak in the p-adics has been fixed.

Polynomial Rings

·A bug in constructing the quotient by the zero ideal has been fixed. Reported by C. Woestijne.

The Integer Ring

·The newly released GMP 4.2 is now linked in.

·A bug in multiplication of integers having more than 230 bits has been fixed. Reported by JBR.

·The functions RandomBits and Ilog2 now handle integers with more than 230 bits properly.