1.There is a set of unmarked states in G that forms a strongly connected component,but with no transition going out of the set ,If the system enters this set of states, then we get what is called a livelock.
2.An automaton G could reach a state x where Γ(x)=∅ but x/∈Xm ,this is called a deadlock because no further event can be executed.
3.A Nondeterministic Automaton,denoted by Gnd,is a six-tuple
Gnd=(X,E∪{ε},fnd,Γ,x0,Xm)
where these objects have the same interpretation as in the definition of deterministic automaton,with the two differences that:
1.fnd is a function fnd :X×E∪{ε}→2x , that is ,fnd(x,e)⊆X whenever it is defined.
2.The initial state may itself be a set of states, that is x0⊆X.
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