Decompositions and bang-bang properties
  In this paper, minimal time and minimal norm control problems are studied. The target sets considered are the origin of state spaces and controls are point-wisely bounded functions. The system stuided in this paper is assumed to have no the null controllability or the backward uniqueness property. In this study, minimal time and minimal norm control problems depend on two parameters, respectively. Whether these problems hold the bang-bang property also depend on the parameters. We study the bang-bang property for different parameters for minimal time and minimal norm control problems, by assuming some kinds of weak controllability and unique continuation property. These two properties automatically hold for general time-invariant finitely dimensional controlled systems. 
Gengsheng Wang, Yubiao Zhang
math.OC