Change log for Magma V2.16-5 (Released 22/1/2010)

Algebraic Geometry

·The computation of affine patches of subschemes of length 1 schemes has been disallowed, consistent with the construction of subschemes of length 0 affine spaces being disallowed.

·A conflict in naming of transcendental generators in functions has been fixed. Reported by C. Quitte.

Coding Theory

·A leak in MinimumWeight has been fixed. Reported by M. Grassl.

Commutative Algebra

·A crash in Saturation for zero ideals has been fixed. Reported by N. Bruin.

·A problem with ChangeRing for boolean polynomial rings has been fixed. Repored by R. Odegard.

Finite Fields

·A bug in printing of non-reduced finite field elements has been fixed.

General Local Fields

·Some fixes to the ramified representation maps for degree 1 fields have been made.

·A fix has been made to FixedField.

Groebner Bases

·A crash in GroebnerBasis(S, d: Faugere := false) for a sequence of boolean polynomials has been fixed.

·A problem in the final interreduction phase for GroebnerBasis(S, d) for a sequence of inhomogeneous polynomials (leading to incorrect results) has been fixed.

Groups

·A runtime error when computing Subgroups of a matrix group over a ring of integers modulo m was incorrect, and has been stopped.

L-functions

·Some fixes and speedups for symmetric powers particularly with modular forms have been made. based on communications with J. B. Conrey.

Lists

·One may now obtain a sublist of a list L via L[S] where S is a sequence of indices.

Matrices

·Problems when computing nullspaces or images of matrices over multivariate rings and fields of fractions have been fixed. Reported by C. Quitte.

·A crash involving huge matrices over algebraic number fields has been fixed. Reported by S. Humphries.

Orders of Quaternion Algebras

·A bug in orders of quaternion algebras over rings other than Z has been fixed.

·Some fixes for RightIdealClasses and Conjugacyclasses over Q.

Polynomial Rings

·A slowness in polynomial squaring over finite fields of large characteristic has been fixed. Reported by Y. Laigle-Chapuy.

·Multivariate polynomial GCD has been sped up in the case that the degree in one variable is much larger than that in the other variables.

·Some very bad inefficiencies in multivariate polynomial powering have been fixed (and a p-adic method is now used for larger exponents). Reported by L. Finotti.

·Problems with loss of precision with polynomial multiplication over inexact rings have been fixed. Reported by A. Mellit.

Semigroups and Monoids

·A bug in the coercion of sequences into monoids has bee fixed, the old code would produce internal errors in case of illegal input.

Sparse Matrices

·A bug involing multiplication of a dense vector by a sparse matrix has been fixed. Reported by E. Thome.