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Questions tagged [automata]

Questions about mathematical devices that read an input stream symbol by symbol and use a state transition map to produce an output stream, maybe using secondary storage.

Automata, or state machines, are mathematical devices often used to define formal languages by way of accepting, or recognizing, or deciding strings belonging to the target language. Commonly encountered varieties of automata are finite automata, pushdown automata, linear-bounded automata, and Turing machines.

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is determinism = non determinism for one counter automata?

This language I think is not accepted by a deterministic one counter but accepted by a non-deterministic one counter : $L = \{a^{i}b^{j}c^{k} \mid (i=j) \vee (j=k) \text{ such that } i\geq0, j\geq0, k\geq0\}$ But how to prove this claim? Or is it…
e_noether
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Black Box Decision problem for NFA

Suppose we are given an NFA $M$ (without $\epsilon$-transitions) that we only know the alphabet $\Sigma$ and the number of states $|Q|$ but we do not know any other details of the NFA. We want to develop a black box algorithm that can test if…
Joe
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Do L-systems have a corresponding automata?

So, I was reading about L-systems and it seems that L-systems are in many ways analogous to context-free grammars. Is there a corresponding automata for this? I can't seem to find anything on the Wikipedia page.
Daniel
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Understanding DPA

DPA denotes “Deterministic Pushdown Automata”. Is the following (*) true regarding DPA: After all symbols of the input sequence are consumed, the input sequence is accepted either (1) if the stack is empty or (2) if the current state of the DPA is…
C. White
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Are statecharts with parallel states NFA, DFA, or none of the above?

I'm looking for formal statements and proofs that I can make when using SCXML statecharts. As such, I'm trying to categorize it properly. SCXML supports hierarchical states. I believe that any hierarchical state machine can be converted into an…
Phrogz
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What's the difference between a Generalized Nondeterministic Finite Automaton (GNFA) and a Generalized Transition Graph (GTG)?

I've recently come across a few articles that talk about a "Generalized Transition Graph" (GTG), but I've never heard of such a thing before. This other answer to a similar question leads me to believe that GNFAs are simply GTGs with a different…
fuentesjr
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Measuring the difficulty of a sequence-to-sequence problem using automata theory

Automata theory measures the difficulty of language recognition problems by using an automaton that can accept or reject for the given string. However, I want to measure the difficulty of a sequence-to-sequence (seq2seq) problem. For instance, what…
user127074
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Show that if Automata $A$ recognize language $L$, there also exists an automata $A′$ that recognize $Double(L)$

I don't know if this question should have better been on math.Stackexchange Let be the operation $Double$ on the words on an $\Sigma$ alphabet which inserts after each character a copy of this character. Thus, $D(ab) = aabb$, $D(abaab) =…
Revolucion for Monica
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Prove that following grammar is ambiguous; S → a | S + S | S S | S* | ( S )

Prove that the following grammar is ambiguous; S → a | S + S | S S | S* | ( S ) checking ambiguity in grammar. the subject of this question is compiler construction and automation. would you please help me find the answer we only have to figure out…
Rimza Shah
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Proving the L' = {w|deleting one symbol from a string in L} is regular when L is regular

I have looked up a question like this online and found this solution. I couldn't understand what the new NFA A' looks like. Could anyone give me an example of NFA A'?
Sloan Kim
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The PDA have to finish reading the input?

I have PDA which has final state that accept 'c' char, and there isn't any cross to other state. The input abca will accept, because there is 'c', or the PDA would stuck?
Ori Eshel
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Give a DFSA that accepts $L_1 = \{x : \#_{01}(x) \mod 3 = 0\}$ using as few states as possible

Let $L_1$ be the language over alphabet $\{0, 1\}$ defined by $L_1 = \{x : \#_{01}(x) \mod 3 = 0\}$. Using as few states as possible, give a DFSA that accepts $L_1$. Also give an appropriate state invariant for your DFSA. I have a regex for it and…
Tree Garen
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self embedded nonterminal in derivation of a Word

consider this question of finding words with no self embedded nonterminal in their derivation. The author(cohen) says that If CFG is in CNF then all the words with length greater than 2^p are guaranteed to have self embedded nonterminal. So, all i…
Ashish kakran
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why it said the "The left recursion has been removed at the cost of an extra non-terminal symbol(E1) and a little extra complexity"?

When I read the book "A Practical approach to compiler construction" the chapter 4 "approaches to syntax analysis" and the section 4.2.3.3 Left Recursion, it says: "The left recursion has been removed at the cost of an extra non-terminal symbol" I…
symphony
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Rectangular Automata

have a question regarding rectangular automata and their derivatives. In each location the derivates are defined by a interval, how are the derivates applied on the variables? Is one value chosen out of the interval and added to the value or do we…
Secr3t
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