autômatos

For several times I hear discussions about Automata, either in chat or in questions/answers. However I particularly do not kn ... ite, finite, Cellular among others. what is an automaton? What do Automata do? What are they for? where do Automata live?

Is there a difference in computational power between a deterministic and a non-deterministic stack automaton?

What is the cellular automaton about? What kind of problem can this solve? Is it something equivalent to Turing machines ?

Well, I still don't understand the logic of using ε-transitions in the NFA, what's the real meaning? Skip state without performing a read? For example, given the regex: a* NFA: DFA:

I recently saw a publication of how Perl was taught to recognize a prime number using regular expressions. The regular expre ... f a number is prime? If so, how is he? If not, what is the proof that this problem cannot be solved through regular language?

Reading a question about basic programming concepts, I come across the following statement: Let A and B be two languages ... irregular language? In the above statement Why is only language B regular? What are the main examples of the two languages?