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D.4.7.4 elim1
Procedure from library elim.lib (see elim_lib).
- Usage:
- elim1(id,arg); id ideal/module, arg can be either an intvec v or a
product p of variables (type poly)
- Return:
- ideal/module obtained from id by eliminating either the variables
with indices appearing in v or the variables appearing in p
- Method:
- elim1 calls eliminate but in a ring with ordering dp (resp. ls)
if the first var not to be eliminated belongs to a -p (resp. -s)
ordering.
- Note:
- no special monomial ordering is required.
Example:
| LIB "elim.lib";
ring r=0,(x,y,t,s,z),dp;
ideal i=x-t,y-t2,z-t3,s-x+y3;
elim1(i,ts);
==> _[1]=y2-xz
==> _[2]=xy-z
==> _[3]=x2-y
module m=i*gen(1)+i*gen(2);
m=elim1(m,3..4); show(m);
==> // module, 6 generator(s)
==> [y2-xz]
==> [0,y2-xz]
==> [xy-z]
==> [0,xy-z]
==> [x2-y]
==> [0,x2-y]
| See also:
elim;
eliminate.
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