Problem:
 F(G(x,A(),B())) -> x
 G(F(H(C(),D())),x,y) -> H(K1(x),K2(y))
 K1(A()) -> C()
 K2(B()) -> D()

Proof:
 Church Rosser Transformation Processor (critical pair closing system, Thm 2.11):
  K2(B()) -> D()
  K1(A()) -> C()
  critical peaks: joinable
  Matrix Interpretation Processor: dim=1
   
   interpretation:
    [K2](x0) = x0,
    
    [K1](x0) = 5x0 + 1,
    
    [D] = 0,
    
    [C] = 0,
    
    [B] = 0,
    
    [A] = 4
   orientation:
    K2(B()) = 0 >= 0 = D()
    
    K1(A()) = 21 >= 0 = C()
   problem:
    K2(B()) -> D()
   Matrix Interpretation Processor: dim=1
    
    interpretation:
     [K2](x0) = x0 + 1,
     
     [D] = 0,
     
     [B] = 4
    orientation:
     K2(B()) = 5 >= 0 = D()
    problem:
     
    Qed