YES

Problem:
 __(__(X,Y),Z) -> __(X,__(Y,Z))
 __(X,nil()) -> X
 __(nil(),X) -> X
 U11(tt()) -> U12(tt())
 U12(tt()) -> tt()
 isNePal(__(I,__(P,I))) -> U11(tt())

Proof:
 Matrix Interpretation Processor: dim=1
  
  interpretation:
   [isNePal](x0) = 7x0 + 7,
   
   [U12](x0) = 2x0 + 6,
   
   [U11](x0) = 7x0 + 7,
   
   [tt] = 2,
   
   [nil] = 2,
   
   [__](x0, x1) = x0 + x1 + 1
  orientation:
   __(__(X,Y),Z) = X + Y + Z + 2 >= X + Y + Z + 2 = __(X,__(Y,Z))
   
   __(X,nil()) = X + 3 >= X = X
   
   __(nil(),X) = X + 3 >= X = X
   
   U11(tt()) = 21 >= 10 = U12(tt())
   
   U12(tt()) = 10 >= 2 = tt()
   
   isNePal(__(I,__(P,I))) = 14I + 7P + 21 >= 21 = U11(tt())
  problem:
   __(__(X,Y),Z) -> __(X,__(Y,Z))
   isNePal(__(I,__(P,I))) -> U11(tt())
  Matrix Interpretation Processor: dim=1
   
   interpretation:
    [isNePal](x0) = 4x0 + 1,
    
    [U11](x0) = x0,
    
    [tt] = 0,
    
    [__](x0, x1) = 4x0 + x1
   orientation:
    __(__(X,Y),Z) = 16X + 4Y + Z >= 4X + 4Y + Z = __(X,__(Y,Z))
    
    isNePal(__(I,__(P,I))) = 20I + 16P + 1 >= 0 = U11(tt())
   problem:
    __(__(X,Y),Z) -> __(X,__(Y,Z))
   Matrix Interpretation Processor: dim=1
    
    interpretation:
     [__](x0, x1) = 2x0 + x1 + 1
    orientation:
     __(__(X,Y),Z) = 4X + 2Y + Z + 3 >= 2X + 2Y + Z + 2 = __(X,__(Y,Z))
    problem:
     
    Qed