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D.5.8.5 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; |