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MAGMA Computational Algebra System

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Next: Arithmetic Fields (Local) Up: Arithmetic Fields (Global) Previous: Algebraic Number Fields


Algebraic Function Fields


Removals and Changes:

  • Removed an unnecessary restriction on orders being maximal when testing whether ideals are prime and in some operations on prime ideals.

  • GaloisGroup of a global function field has been reimplemented.

  • The MaximalOrder computation in Kummer extensions has been sped up by avoiding the construction of intermediate p-maximal orders. (V2.15-3)

  • The application of the residue field map to inputs with denominators has been improved. (V2.15-6)

  • Some expensive computations with orders have been avoided which has considerable effect in maximal order computations. (V2.15-6)


New Features:

  • A new algorithm has been implemented for the computation of p-maximal and maximal orders in Artin-Schreier extensions.

  • Computing a prime decomposition of a prime which totally ramifies in an Artin-Schreier or a Kummer extension now uses a similar algorithm to that implemented for computation of p-maximal and maximal orders.

  • The algorithm of Klüners and van Hoeij for computing subfields of a generic field has been implemented and is used to compute the Subfields of a global function field.

  • InfiniteDivisor, FiniteDivisor, FiniteSplit of a divisor have been added.

  • A sub constructor has been added for function fields.


Bug Fixes:

  • The ext<> constructor for infinite orders of function fields has been fixed.

  • It is now possible to take the Valuation of a rational function at a place, after the fix of an input check. (V2.15-3)

  • The computation of p-maximal orders of function fields which are a direct Kummer extension of a rational function field has been fixed. (V2.15-6)

  • A problem with product representations has been fixed. (V2.15-7)

  • Some bugs resulting in incorrect answers from Expand and the application of completion maps have been fixed. (V2.15-8, V2.15-10)


next up previous
Next: Arithmetic Fields (Local) Up: Arithmetic Fields (Global) Previous: Algebraic Number Fields

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