YES(?,POLY) 'Pop* with parameter subtitution (timeout of 60.0 seconds)' ----------------------------------------------------------- Answer: YES(?,POLY) Input Problem: innermost runtime-complexity with respect to Rules: { sum(0()) -> 0() , sum(s(x)) -> +(sum(x), s(x)) , +(x, 0()) -> x , +(x, s(y)) -> s(+(x, y))} Proof Output: The input was oriented with the instance of POP* as induced by the precedence sum > + and safe mapping safe(sum) = {}, safe(0) = {}, safe(s) = {1}, safe(+) = {1} . For your convenience, here is the input in predicative notation: Rules: { sum(0();) -> 0() , sum(s(; x);) -> +(s(; x); sum(x;)) , +(0(); x) -> x , +(s(; y); x) -> s(; +(y; x))}