YES TRS: fib(0()) -> 0() fib(s(0())) -> s(0()) fib(s(s(x))) -> +(fib(s(x)),fib(x)) +(x,0()) -> x +(x,s(y)) -> s(+(x,y)) max/plus interpretations on N: fib_A(x1) = max{4, 1 + x1} fib#_A(x1) = max{2, -6} 0_A = 5 0#_A = 1 s_A(x1) = max{5, 2} s#_A(x1) = max{0, -5} +_A(x1,x2) = max{6, x1, 3} +#_A(x1,x2) = max{1, -3, -4} precedence: fib > s > 0 = +