diff --git a/Concurrent Systems/notes/11 - non so cosa faremo oggi.md b/Concurrent Systems/notes/11 - non so cosa faremo oggi.md
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+
+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]
+>M1 and M2 are *language equivalent* if and only if L(M1)=L(M2)
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