YES 3 decompositions #1 ----------- 1: from(x1) -> :(x1,from(s(x1))) #2 ----------- 2: ++(++(x1,x2),x3) -> ++(x1,++(x2,x3)) 3: ++(x1,++(x2,x3)) -> ++(++(x1,x2),x3) 4: ++(0(),x1) -> x1 5: ++(x1,0()) -> x1 6: hd(c(x1)) -> x1 7: hd(++(c(x1),x2)) -> x1 #3 ----------- 2: ++(++(x1,x2),x3) -> ++(x1,++(x2,x3)) 3: ++(x1,++(x2,x3)) -> ++(++(x1,x2),x3) 4: ++(0(),x1) -> x1 5: ++(x1,0()) -> x1 8: *(0(),x2) -> 0() 9: *(s(x1),x2) -> ++(x2,*(x1,x2)) @Development Closedness --- R 1: from(x1) -> :(x1,from(s(x1))) --- S 1: from(x1) -> :(x1,from(s(x1))) @Jouannaud and Kirchner's criterion --- R 2: ++(++(x1,x2),x3) -> ++(x1,++(x2,x3)) 3: ++(x1,++(x2,x3)) -> ++(++(x1,x2),x3) 4: ++(0(),x1) -> x1 5: ++(x1,0()) -> x1 6: hd(c(x1)) -> x1 7: hd(++(c(x1),x2)) -> x1 --- S 2: ++(++(x1,x2),x3) -> ++(x1,++(x2,x3)) 3: ++(x1,++(x2,x3)) -> ++(++(x1,x2),x3) 4: ++(0(),x1) -> x1 5: ++(x1,0()) -> x1 6: hd(c(x1)) -> x1 7: hd(++(c(x1),x2)) -> x1 @Jouannaud and Kirchner's criterion --- R 2: ++(++(x1,x2),x3) -> ++(x1,++(x2,x3)) 3: ++(x1,++(x2,x3)) -> ++(++(x1,x2),x3) 4: ++(0(),x1) -> x1 5: ++(x1,0()) -> x1 8: *(0(),x2) -> 0() 9: *(s(x1),x2) -> ++(x2,*(x1,x2)) --- S 2: ++(++(x1,x2),x3) -> ++(x1,++(x2,x3)) 3: ++(x1,++(x2,x3)) -> ++(++(x1,x2),x3) 4: ++(0(),x1) -> x1 5: ++(x1,0()) -> x1 8: *(0(),x2) -> 0() 9: *(s(x1),x2) -> ++(x2,*(x1,x2))