YES 1 decompositions #0 ----------- 1: +(0(),y) -> y 2: +(s(x),y) -> s(+(x,y)) 3: s(s(x)) -> x @Jouannaud and Kirchner's criterion --- R 1: +(0(),y) -> y 2: +(s(x),y) -> s(+(x,y)) 3: s(s(x)) -> x --- S 1: +(0(),y) -> y 2: +(s(x),y) -> s(+(x,y)) 3: s(s(x)) -> x