ring_of_q_difference_operators

string ring_of_q_difference_operators
  
This command has not been maintained since 1996. So, there may be
troubles if it is used with new features of kan/sm1.
  
This command is used to define a ring of q-difference operators 
with the macros define_qring, weight_vector and elimination_order.
Note that you should use this macro with define_qring instead of
define_ring.
The user cannot use the variable names h, e, q and E.
cf. show_ring, system_variable --- CurrentRing
    print_switch_status, switch_function
Example: [(x,y,z) ring_of_q_difference_operators (Qx,Qy) elimination_order 0] define_qring
         Qx,Qy, and Qz are corresponding q-difference operators to the 
         space variables x, y and z ( Qx x = (q) x Q).