master-degree-notes/Concurrent Systems/notes/11 - non so cosa faremo oggi.md

A (finite non-deterministic) automaton is a quintuple M = (Q,Act,q0,F,T), where:

• Q is the set of states
• Act is the set of actions
• q0 is the starting state
• F is the set of final states
• T is the transition relation (T ⊆ Q × Act × Q)

Automata Behaviour: language equivalence (where L(M) is the set of all the sequences of input characters that bring the automaton M from its starting state to a final one)

[!note] Language equivalence M1 and M2 are language equivalent if and only if L(M1)=L(M2)

By considering the starting states as also final, they both generate the same language, i.e.:

(20.(tea + 20.coffee))∗ = (20.tea + 20.20.coffee)∗

But, do they behave the same from the point of view of an external observer??