“…Although both homotopy groups are isomorphic to the set of all integers, Z, the dependence relationships between the corresponding minimum energies and topologies are drastically different, which lead to the existence of different types of solitons: point-like ones in the Skyrme theory but knot-like ones in the Faddeev theory. More precisely, let us use E and Q to collectively denote the energy and topological invariant in either the Skyrme theory or the Faddeev theory, u is any static field configuration, N is a given integer, and Such a property is also commonly seen in previously well-studied gauge field theory soliton configurations including vortices and monopoles (Bogomol'nyi 1976;Actor 1979;Jaffe & Taubes 1980;Yang 2001) and instantons (Witten 1977;Atiyah et al 1978;Actor 1979;Rajaraman 1982;Nash & Sen 1983;Freed & Uhlenbeck 1991;Yang 2001). On the other hand, however, for the Faddeev theory case, we have, instead, the sublinear asymptotics E N wjN j 3=4 ; ð1:3Þ which is analogous to the ropelength energy, crossing number relation EwN p (3/4%p%1) stated earlier but is uncommonly seen in quantum field theory.…”