YES (ignored inputs)COMMENT doi:10.1007/978-3-319-43144-4_18 [110] Example 4 Rewrite Rules: [ f(a,a,b,b) -> f(c,c,c,c), a -> b, a -> c, b -> a, b -> c ] Apply Direct Methods... Inner CPs: [ f(b,a,b,b) = f(c,c,c,c), f(a,b,b,b) = f(c,c,c,c), f(c,a,b,b) = f(c,c,c,c), f(a,c,b,b) = f(c,c,c,c), f(a,a,a,b) = f(c,c,c,c), f(a,a,b,a) = f(c,c,c,c), f(a,a,c,b) = f(c,c,c,c), f(a,a,b,c) = f(c,c,c,c) ] Outer CPs: [ b = c, a = c ] not Overlay, check Termination... unknown/not Terminating unknown Knuth & Bendix Linear Development Closed Direct Methods: CR Combined result: CR 503.trs: Success(CR) (12 msec.)