YES We show the termination of the TRS R: +(|0|(),y) -> y +(s(x),y) -> s(+(x,y)) +(s(x),y) -> +(x,s(y)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: +#(s(x),y) -> +#(x,y) p2: +#(s(x),y) -> +#(x,s(y)) and R consists of: r1: +(|0|(),y) -> y r2: +(s(x),y) -> s(+(x,y)) r3: +(s(x),y) -> +(x,s(y)) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: +#(s(x),y) -> +#(x,y) p2: +#(s(x),y) -> +#(x,s(y)) and R consists of: r1: +(|0|(),y) -> y r2: +(s(x),y) -> s(+(x,y)) r3: +(s(x),y) -> +(x,s(y)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic path order with precedence: precedence: s > +# argument filter: pi(+#) = 1 pi(s) = [1] The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains.