YES

Problem:
 f(a(),x) -> g(a(),x)
 g(a(),x) -> f(b(),x)
 f(a(),x) -> f(b(),x)

Proof:
 Polynomial Interpretation Processor:
  dimension: 1
  interpretation:
   [b] = 0,
   
   [g](x0, x1) = x1 + x0x0,
   
   [f](x0, x1) = 3x0 + x1 + 5,
   
   [a] = 4
  orientation:
   f(a(),x) = x + 17 >= x + 16 = g(a(),x)
   
   g(a(),x) = x + 16 >= x + 5 = f(b(),x)
   
   f(a(),x) = x + 17 >= x + 5 = f(b(),x)
  problem:
   
  Qed