YES We show the termination of the TRS R: +(-(x,y),z) -> -(+(x,z),y) -(+(x,y),y) -> x -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: +#(-(x,y),z) -> -#(+(x,z),y) p2: +#(-(x,y),z) -> +#(x,z) and R consists of: r1: +(-(x,y),z) -> -(+(x,z),y) r2: -(+(x,y),y) -> x The estimated dependency graph contains the following SCCs: {p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: +#(-(x,y),z) -> +#(x,z) and R consists of: r1: +(-(x,y),z) -> -(+(x,z),y) r2: -(+(x,y),y) -> x The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. lexicographic path order with precedence: precedence: - > +# argument filter: pi(+#) = [1] pi(-) = [1, 2] 2. lexicographic path order with precedence: precedence: - > +# argument filter: pi(+#) = [1] pi(-) = [1, 2] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.