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7.5.5.0. fl2poly
Procedure from library dmodapp.lib (see dmodapp_lib).
- Usage:
- fl2poly(L,s); L a list, s a string
- Return:
- poly
- Purpose:
- reconstruct a monic polynomial in one variable from its factorization
- Assume:
- s is a string with the name of some variable and
L is supposed to consist of two entries:
- L[1] of the type ideal with the roots of a polynomial
- L[2] of the type intvec with the multiplicities of corr. roots
Example:
| | LIB "dmodapp.lib";
ring r = 0,(x,y,z,s),Dp;
ideal I = -1,-4/3,0,-5/3,-2;
intvec mI = 2,1,2,1,1;
list BS = I,mI;
poly p = fl2poly(BS,"s");
p;
==> s7+7s6+173/9s5+233/9s4+154/9s3+40/9s2
factorize(p,2);
==> [1]:
==> _[1]=s+2
==> _[2]=3s+4
==> _[3]=3s+5
==> _[4]=s
==> _[5]=s+1
==> [2]:
==> 1,1,1,2,2
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