“…Definition 1 (Inclusion Principle) A systemS is an expansion of the system S if there exist transformations (U, V, R, S) as in (2) such that, for any initial state x 0 ∈R n and any input u(t)∈R m , ifx 0 =V x 0 andũ(t)=Ru(t) then x(t; x 0 , u)=Ux(t; V x 0 , Ru) for all t≥0.…”