Change log for Magma V2.15-9 (Released 1/5/2009)

Function Fields

·A bug with sets of rational function field elements (where the hashing was wrong sometimes) has been fixed. Reported by M. Grassl.

Groups

·The missing irreducible subgroups of GL(2,2) in the IrreducibleMatrixGroup function have been found. Bug reported by C. Roney-Dougal.

·Improved algorithms for computing the soluble radical of matrix groups over the integers and rationals have been included.

·A faster method for computing ComplementEquationsMatrix for a module over the rationals has been adopted.

·The functions RWSGroup and RWSMonoid have been stopped from leaving an empty file in the /tmp directory at each call. Bug reported by S. Humphries and D. Holt.

Invariant Rings

·A bug in FundamentalInvariants for invariant rings of matrix groups which were not monomial has been fixed. Reported by M. Grassl.

·A crash in HomogeneousModuleTestBasis, when given zero polynomials, has been fixed. Reported by M. Grassl.

Lattices

·A crash when taking an ActionGenerator of a G-Lattice has been fixed.

Modular Symbols

·The empty sequence may now be coerced into the space of modular symbols.

Polynomial Rings

·A bug in multivariate resultant over finite fields (arising in factorization of polynomials over function fields) has been fixed. Reported by N. Bruin.

Sparse Matrices

·A bug in ModularSolution, which would result in a crash whenever Lanczos was selected without also selecting verbose output, has been fixed. Reported by C. Diem.