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D.12.7.13 sturmhaseq
Procedure from library rootsur.lib (see rootsur_lib).
- Usage:
- sturmhaseq(P); P poly.
- Return:
- list: the non-zero polynomials of the Sturm-Habicht sequence of P
- Assume:
- P is a univariate polynomial.
- Theory:
- The Sturm-Habicht sequence (also subresultant sequence) is closely
related to the Sturm sequence, but behaves better with respect to
the size of the coefficients. It is defined via subresultants.
See: Basu, Pollack, Roy, Algorithms in Real Algebraic Geometry,
Springer, 2003.
Example:
| | LIB "rootsur.lib";
ring r = 0,x,dp;
poly p = x5-x4+x-3/2;
list l = sturmhaseq(p);
l;
==> [1]:
==> 132949/16
==> [2]:
==> -25x-332
==> [3]:
==> -16x2+42x-24
==> [4]:
==> 4x3-20x+73/2
==> [5]:
==> 5x4-4x3+1
==> [6]:
==> x5-x4+x-3/2
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See also:
sturm;
sturmha;
sturmseq.
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