(VAR x y z) (RULES f(x,y,z) -> g(<=(x,y),x,y,z) g(true,x,y,z) -> z g(false,x,y,z) -> f(f(p(x),y,z),f(p(y),z,x),f(p(z),x,y)) p(0) -> 0 p(s(x)) -> x ) (COMMENT Example 4.57 in \cite{SK90})