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D.4.3.4 nselect
Procedure from library elim.lib (see elim_lib).
- Usage:
- nselect(id,n[,m]); id a module or ideal, n, m integers
- Return:
- generators of id not containing the variable n [up to m]
Example:
| LIB "elim.lib";
ring r=0,(x,y,t,s,z),(c,dp);
ideal i=x-y,y-z2,z-t3,s-x+y3;
nselect(i,3);
==> _[1]=x-y
==> _[2]=-z2+y
==> _[3]=y3-x+s
module m=i*(gen(1)+gen(2));
show(m);
==> // module, 4 generator(s)
==> [x-y,x-y]
==> [-z2+y,-z2+y]
==> [-t3+z,-t3+z]
==> [y3-x+s,y3-x+s]
show(nselect(m,3,4));
==> // module, 2 generator(s)
==> [x-y,x-y]
==> [-z2+y,-z2+y]
| select, select1
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