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IdealBasisUpperHNF

The basis of the ideal transformed in upper HNF.

Syntax:

M := IdealBasisUpperHNF(I);

list
  M  
two elements, the denominator and the basis matrix
ideal
  I  

See also:  IdealBasisLowerHNF, IdealUpperHNFTrans

Description:

This returns the basis of the ideal transformed in (right) upper HNF. Either it is computed from a plain basis (which can be seen with IdealBasis) or from a 2-element representation. Once computed the basis in upper HNF is stored in the ideal data structure so it has not to be computed again. In most cases IdealBasis and IdealBasisUpperHNF are identical.


Example:


kash> o := Order(Poly(Zx, [1, 6, 6, 6]));;
kash> alpha := Elt(o, [0, 1, 0]);;
kash> I := Ideal(6, alpha);
<6, [0, 1, 0]>
kash> IdealBasisUpperHNF(I);
> [ 1, [6 0 0]
    [0 1 0]
    [0 0 1] ]


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