New certi cate-oriented access control systems are based on delegation of privileges. In these scenarios, resource guards have an ACL which delegates to some authorization or naming authorities the right to manage the access to the controlled resources. These authorities can issue certi cates delegating these permissions to other subordinates authorities, or to speci c users. In this way, the g...

We study the controllability of linear distributed control systems described by differential equations in Banach spaces with a degenerate operator at the derivative. A homogeneous part of equations has a degenerate strongly continuous resolving semigroup. For such system with, generally speaking, a time-dependent bounded operator at the control function we find the criteria of ε-controllability...