0 QTRS
f(s(x)) → f(id_inc(c(x, x))) f(c(s(x), y)) → g(c(x, y)) g(c(s(x), y)) → g(c(y, x)) g(c(x, s(y))) → g(c(y, x)) g(c(x, x)) → f(x) id_inc(c(x, y)) → c(id_inc(x), id_inc(y)) id_inc(s(x)) → s(id_inc(x)) id_inc(0) → 0 id_inc(0) → s(0)