-- A basis consists of:
 -- a number of Fermionic modes or spin-orbitals
NF=6;
 -- a number of Bosonic modes (phonon modes, ...)
NB=0;
 -- an index relating the spinorbitals to quantum 
 -- numbers we assign to them.  For a p-shell we would
 -- like the have 6 spinorbitals with the quantum
 -- numbers spin up ml=-1,ml=0,ml=1 and spin down
 -- with ml=-1, ml=0, ml=1
IndexDn={0,2,4};
IndexUp={1,3,5};
-- the code knows that a 3 fold degenerate shell 
-- has l=1 and ml=-1, 0 and 1 are assigned to 
-- them automatically

-- we can now create the spin operators on this basis
OppSx=NewOperator("Sx",NF,IndexUp,IndexDn);
OppSy=NewOperator("Sy",NF,IndexUp,IndexDn);
OppSz=NewOperator("Sz",NF,IndexUp,IndexDn);

-- and print them
print(OppSx)
print(OppSy)
print(OppSz)

print("=================================");
-- the spin operators commute such that 
-- Sx * Sy - Sy * Sx = I Sz. This can easily be 
-- checked by multiplying operators
OppNill = OppSx * OppSy - OppSy * OppSx - I * OppSz;

-- OppNill should be a zero operator
print(OppNill)

-- Printing indeed showed only zero's, but the are 
-- still stored. The above equation should return
-- an operator of lenght zero. in order to remove
-- small values from the operator one can chop these
OppNill=Chop(OppNill);

-- secondly the name of the operator is a generic 
-- "operator". Not so nice, so lets set the name
OppNill.Name = "Sx * Sy - Sy * Sx - I Sz";

-- now we can print again.
print(OppNill)