D.5.8.4 is_ci

Procedure from library sing.lib (see sing_lib).

Usage:

is_ci(i); i ideal

Return:

intvec = sequence of dimensions of ideals (j[1],...,j[k]), for k=1,...,size(j), where j is minimal base of i. i is a complete intersection if last number equals nvars-size(i)

Note:

dim(0-ideal) = -1. You may first apply simplify(i,10); in order to delete zeroes and multiples from set of generators
printlevel >=0: display comments (default)

Example:

LIB "sing.lib";
int p      = printlevel;
printlevel = 1;                // display comments
ring r     = 32003,(x,y,z),ds;
ideal i    = x4+y5+z6,xyz,yx2+xz2+zy7;
is_ci(i);
→ // complete intersection of dim 0
→ // dim-sequence:
→ 2,1,0
i          = xy,yz;
is_ci(i);
→ // no complete intersection
→ // dim-sequence:
→ 2,2
printlevel = p;