“…Moreover we have a partial order on the set of prime knots, by setting K ≥ K if there is an epimorphism G( K) → G(K) (see, for example, [32,Proposition 3.2]). Epimorphisms among link groups have received considerable attention and they have been studied in various places in the literature (see [1,2,5,6,10,11,15,16,17,25,27,30,32,33,34,35,36] and references therein).…”