Change log for Magma V2.15-15 (Released 23/10/2009)

Algebras

·Orders of algebras over number fields constructed from a ring and a sequence of algebra elements now store their ideals as all other orders over orders do.

Commutative Algebra

·FittingIdeal now handles the zero ideal properly. Reported by E. Rains.

·Some bugs in modules over local polynomial rings have been fixed. Reported by E. Rains.

·The simple convenience function Degree has been added for a homogeneous ideal in a polynomial ring with all variables of weight one.

EllipticCurves

·In IsogenyFromKernel, the case of the entire curve as the kernel subgroup scheme has been properly disallowed. This previously resulted in crashes over finite fields.

Integer Ring

·In the ECPP algorithm, the internal parameters have been changed again to avoid failures that occurred when verifying primality of certain smallish primes in IsPrime or PrimalityCertificate. Examples of failure reported by J. Kimberley.

Language

·A crash when deleting huge numbers of variables in one go has been fixed. Reported by M. Kirschmer.

Lazy Power Series

·In PrintToPrecision, a newline has been added after the printout of a lazy power series. Problem reported by M. Grassl.

ModularCurves

·IsModularCurve has been changed to a basic intrinsic that simply returns whether a scheme is of type CrvMod or not. Problem reported by Jean-Marie Maillard.

Module Theory

·Some bugs involving zero modules have been fixed. Reported by E. Rains.