| LIB "central.lib";
ring AA = 0,(x,y,z),dp;
matrix D[3][3]=0;
D[1,2]=-z; D[1,3]=2*x; D[2,3]=-2*y;
def A = nc_algebra(1,D); setring A; // this algebra is U(sl_2)
// There is only one Cartan variable - z in U(sl_2),
// it must go 1st:
variablesSorted();
==> _[1]=z
==> _[2]=y
==> _[3]=x
|