def dmp_zero_p(f, u):
 while u:
  if (len(f) != 1):
   return False
  f = f[0]
  u -= 1
 return (not f)

def dmp_zero_p ( f , u ) : while u : if ( len ( f ) != 1 ) : return False f = f [ 0 ] u -= 1 return ( not f )
return true if f is zero in k[x] .