“…"Simple systems" with trivial foliation like uncoupled harmonic oscillators have globally continuous and smooth energy surfaces. For many of the non-simple systems considered so far [1,2,3,4,5,6,7,8,9], the energy surfaces are nonsmooth at separatrices, but, nevertheless, continuous or can be made continuous by a reduction of the system's discrete symmetries. In [10,11,9] such systems are referred to as "one-component systems".…”