D.5.1.10 singularity

Procedure from library classify.lib (see classify_lib).

Usage:

singularity(t, l); t=string (name of singularity),
l=list of integers/polynomials (indices/parameters of singularity)

Compute:

get the singularity named by type t from the database. list l is as follows:
l= k [,r [,s [,a [,b [,c [,d]..]: k,r,s=int a,b,c,d=poly.
The name of the dbm-database file is: NFlist.[dir,pag]. The file is found in the current directory. If it does not exist, please run the script MakeDBM first.

Return:

Normal form and corank of the singularity named by type t and its index (indices) l.

Example:

LIB "classify.lib";
ring r=0,(x,y,z),(c,ds);
init_debug(0);
singularity("E[6k]",6);
→ [1]:
→    x3+xy13+y19
→ [2]:
→    2
singularity("T[k,r,s]", 3, 7, 5);
→ [1]:
→    x3+xyz+z5+y7
→ [2]:
→    3
poly f=y;
singularity("J[k,r]", 4, 0, 0, f);
→ [1]:
→    x3+x2y4+y13
→ [2]:
→    2