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D.6.15.19 tangentcone

Procedure from library sing.lib (see sing_lib).

Usage:
tangentcone(id [,n]); id = ideal, n = int

Return:
the tangent cone of id

Note:
The procedure works for any monomial ordering.
If n=0 use std w.r.t. local ordering ds, if n=1 use locstd.

Example:
 
LIB "sing.lib";
ring R = 0,(x,y,z),ds;
ideal i  = 7xyz+z5,x2+y3+z7,5z5+y5;
tangentcone(i);
==> _[1]=x2
==> _[2]=7xyz
==> _[3]=y5+5z5
==> _[4]=7y4z
==> _[5]=35z6