Controlled invariant subspace
Appearance
Controlled Invariant Subspace A subspace V is called controlled invariant , if for any x0 of V and such an input u, xu(t,x0) is in V , for all t nonnegative.
Theorem:
Let V be a subspace of X.Then the following are equivalent
i)V is controlled invariant
ii)AV is in V + Im B
iii)There exist a feedback F such that (A+BF)V is in V