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D.6.20.6 is_is
Procedure from library sing.lib (see sing_lib).
- Usage:
- is_is(id); id ideal or poly
- Return:
- intvec = sequence of dimensions of singular loci of ideals
generated by id[1]..id[i], k = 1..size(id);
dim(0-ideal) = -1;
id defines an isolated singularity if last number is 0
- Note:
- printlevel >=0: display comments (default)
Example:
| | LIB "sing.lib";
int p = printlevel;
printlevel = 1;
ring r = 32003,(x,y,z),ds;
ideal i = x2y,x4+y5+z6,yx2+xz2+zy7;
is_is(i);
==> // dim of singular locus = 0
==> // isolated singularity if last number is 0 in dim-sequence:
==> 2,1,0
poly f = xy+yz;
is_is(f);
==> // dim of singular locus = 1
==> // isolated singularity if last number is 0 in dim-sequence:
==> 1
printlevel = p;
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