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Questions tagged [automata]

In theoretical computer science, automata theory is the study of abstract 'mathematical' machines or systems and the computational problems that can be solved using these machines. These abstract machines are called automata. ("Automata", Wikipedia)

From Wikipedia,

Automata, or automata theory, is the study of mathematical objects called abstract machines or automata and the computational problems that can be solved using them. Automata comes from the Greek word αὐτόματα meaning "self-acting".

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Proof the language is regular or not regular using Pumping lemma?

Can any one help to figure out that L = { am bn, m ≥ n + 2, m ≤ 3 } is regular or not using pumping lemma, It seems to be a bit difficult to prove. I have tried to used pumping lemma and it shows that it is regular language but i am really…
Rahim Khalid
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Transform grammar into LL(1), identify whether it is LL(1)

I cannot quite understand how to determine whether grammar is LL(1) or not. I have been given the following grammar: S → Y | 1X X → 1X | 0 Y → Y0|1X1|2X2 I stated that this grammar is not LL(1) because it Y0 is left recursive. So I came up with…
AlenEviLL
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fsm with gevent with its own (infinite) call stack

I was wondering how can I define a finite state machine which has loops using a greenlet in python without causing a stckoverflow. From https://greenlet.readthedocs.org/en/latest/: "A “greenlet” is a small independent pseudo-thread. Think about it…
krish7919
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How to determine whether finite-state automata is deterministic?

How to write a Java code that will determine whether the given automaton is deterministic. What I have is a class that represents automata and it has the following five variables: int alphabet_size; int n_states; int delta[][]; int…
AlenEviLL
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Scapy's automata, 2 times executing cycle

I have written this code: from scapy.layers.inet import ICMP,IP from scapy.all import Raw class GetIP(Automaton): def parse_args(self, **kargs): Automaton.parse_args(self, **kargs) def master_filter(self, pkt): return…
Valeriy Polischuk
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Constructing a finite automaton to prove L is regular

Considering a language L, let L′ be the set of all first halves of strings in L so that L′ ={x| for some y,|x|=|y|and xy ∈ L} Please prove that if L is regular, then L′ is also regular by constructing a finite automaton for L′. I am having some…
hashes4merkle
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Is there any particular reason this type is not a generalized DFA? And if so, what is it really?

I'm putting together a library of fundamental structures in Scala for use in either production or for personal study. I'm focusing on clear descriptions of said structures in either type theory, cat theory, set theory. One of the types, abstract…
Mzk Levi
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Pumping Lemma On Context Free Language

For the language {a^2^n | n >= 0} I understand that first some k is chosen, and then z = uvwxy such that vx != epsilon and #(vwx) <= k, but I can't think of any i which proves that this language is not context free.
VadislavBby
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Draw directed edge of an automata in Java

I am required to write something similar to graphviz. I have already managed to draw the nodes so that they do not overlap and to connect their center with a quadratic Bezier curve, but I am facing the following problem with the directionality of a…
Eszter
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Creating an NFA Diagram where one of the last three chars is an 'a'

having some trouble with this question creating an NFA, would appreciate some help L consists of all words over {a,b} has an 'a' as one of the last 3 characters in the word the length of the words can be less than 3 'a' is in the language, while…
user2910569
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Simple explanation of PDA accept states?

I've been trying to find a super simple explanation of Push-Down Automaton. This is what I've come up with so far: A PDA has three operations: A push to the stack; given an input state, input symbol, and the top stack symbol A pop from the stack;…
user3470131
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How can I make a steady automata in JavaScript?

I'm working on a javascript game and I've got an automata system controlling game time and sprite animation as well as giving a hand to the path finding system for timing and such. My problem is on slow browsers the javascript loop I'm using for…
Robert Hurst
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Turing machine that goes left on first symbol

I have a turing machine with transitions given by the following table I'm inputting the string aaaa. So if I look at the first symbol "a" in state A, it says to replace it with an X, go into state B, and move Left. This is where I'm confused. How…
user3000731
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What is the difference between acceptability,computability,decidability and recognizability in automata theory?

When we say recursively enumerable languages are recognizable and recursive languages are acceptable by turning machine, what is the difference between these two terms? And also what is the meaning of TM Computable ?
Rishi
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Is this language regular? {0^n 1^m | m != n}, I don't understand the direct proof by pumping length

There is a direct way to prove it: If p is the pumping length and we take the string s = 0p1p+p!, then no matter what the decomposition s = xyz is the string xy1+p!/|y|z will equal 0p+p!1p+p! which is not in the language. I don't understand the…
Harshal Carpenter
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