Change log for Magma V2.18-3 (Released 27/1/2012)

Algebras

·A crash to do with generators of a 0-dimensional algebra has been fixed. Reported by S. Humphries.

Basics

·The output of ContinuedFraction is properly truncated, and the function no longer uses PARI. Reported by M. Bright.

Function Fields

·The comment for the Completion intrinsics has been expanded to explain the precision used. The Precision parameter is now available for Completion of fields and orders in relative representation.

Groebner Bases

·A crash in GroebnerBasis with the PairsLimit parameter has been fixed. Reported by W. Whistler.

·A problem in Variety where the second argument is a complex field has been fixed. Reported by C. Zickert.

Groups

·A crash when constructing a homomorphism from a matrix group to an automorphism group has been fixed. Reported by D. Holt.

·The name of the maximal subgroup of order 1081 of the Baby Monster group (as returned by MaximalSubgroupsData) has been corrected to 47:23. Reported by M. Giudici.

·A bug in the IsolProcess family of functions has been fixed. Reported by A. Kasprzyk.

·A bug in isomorphism testing between PC groups was resolved.

·Many improvements to the p-group automorphism group code were made, particularly for large examples.

·A crash computing LowIndexSubgroups of a Coxeter group represented as a permutation group has been fixed. Reported by Stefan Elsenhans.

·There is a new access function for automatic groups: WordDifferences. This returns the sequence of words labelling the states of the word difference machine of the group.

·Magma level printing of an automatic group is now supported.

·A bug in ClassicalMaximals, with classes set to 6 and the normaliser option true, has been fixed. Reported by M. Giudici, fixed by D. Holt.

·The optional database with transitive group identification data for degree 32 [Trn32IdData.tar.gz] is now available.

·A bug in computing the inverse of an endomorphism of a free fp-group has been fixed. Reported by E. O'Brien.

Lattices

·Some bugs in G-lattices and () for lattice elements have been fixed.

Linear Programming

·The printing (both normal and verbose) of LP processes has been improved.

Number Fields

·ClassGroupCyclicFactorGenerators has been fixed when the class group map is not completely computed.

·Improve algorithm selection for Subfields of a number field in absolute representation.

·Calculation of generators of principal ideals has been improved when such generators are large.

Polynomial Rings

·Norm of a polynomial over a field whose defining polynomial is not over its coefficient field has been fixed. Reported by D. Gru.

Schemes

·The base ring of an ambient space is now printed with the ambient.

System

·Objects of type Process now have a parent and may consequently be used in sequences.