YES exiting with thread! (VAR x y z ) (RULES p(x,0) -> x p(x,s(y)) -> s(p(x,y)) f(0) -> 0 f(s(0)) -> s(0) f(s(s(z))) -> p(f(s(z)),f(z)) n(b(x,y)) -> b(p(x,y),x) u(b(x,y)) -> p(x,y) g(x) -> b(f(s(x)),f(x)) )