YES 4: f(h(x1),h(x2)) -> f(x2,x1) 5: f(x1,x2) -> f(x2,x1) 6: g(x1) -> h(x1) 7: h(x1) -> g(x1) @Rule Labeling --- R 4: f(h(x1),h(x2)) -> f(x2,x1) 5: f(x1,x2) -> f(x2,x1) 6: g(x1) -> h(x1) 7: h(x1) -> g(x1) --- S 4: f(h(x1),h(x2)) -> f(x2,x1) 5: f(x1,x2) -> f(x2,x1) 6: g(x1) -> h(x1) 7: h(x1) -> g(x1) NOTE: input TRS is reduced original is 1: f(g(x1),g(x2)) -> f(g(x1),h(x2)) 2: f(h(x1),g(x2)) -> f(g(x1),g(x2)) 3: f(g(x1),h(x2)) -> f(x1,x2) 4: f(h(x1),h(x2)) -> f(x2,x1) 5: f(x1,x2) -> f(x2,x1) 6: g(x1) -> h(x1) 7: h(x1) -> g(x1) reduced to 4: f(h(x1),h(x2)) -> f(x2,x1) 5: f(x1,x2) -> f(x2,x1) 6: g(x1) -> h(x1) 7: h(x1) -> g(x1)