code: def lbp_sub(f, g):
      """
      Subtract labeled polynomial g from f.
  
      The signature and number of the difference of f and g are signature
      and number of the maximum of f and g, w.r.t. lbp_cmp.
      """
      if sig_cmp(Sign(f), Sign(g), Polyn(f).ring.order) < 0:
          max_poly = g
      else:
          max_poly = f
  
      ret = Polyn(f) - Polyn(g)
  
      return lbp(Sign(max_poly), ret, Num(max_poly))
  
imports: from sympy.core.symbol import Dummy
  from sympy.polys.monomials import monomial_mul, monomial_lcm, monomial_divides, term_div
  from sympy.polys.orderings import lex
  from sympy.polys.polyerrors import DomainError
  from sympy.polys.polyconfig import query
label_desc: Use image node_id 12 for calling a global function with example usage: lbp_sub(f, g) and returns: lbp