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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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Wa-Tor like cellular automata. In which order should the cells be updated?

Some time ago I've written a Wa-Tor like cellular automata (see Wikipedia) but with a few more species and a little smarter species. Except for a lot of fine tuning to get a stable system it was quite simple and worked well. However since that time…
katzenversteher
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A square root computing turing machine

I think i am close to this answer but still to confirm can we create a turing machine(At least in Principle) which can work on real number computation and give exact results?**For example finding square root of an integer.(whose output would be a…
bashrc
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How can I prove this dFa is minimal?

I am trying prove that this DFA is minimal for this Union.
CS_student
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PDA for {a^n b^m | n<=m<=2n}

Can someone help me design PDA for {a^n b^m | n<=m<=2n}. Can you please design one with explanation.
RJ Naskar
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How many equivalence classes in the RL relation for {w in {a, b}* | (#a(w) mod m) = ((#b(w)+1) mod m)}

How many equivalence classes in the RL relation for {w in {a, b}* | (#a(w) mod m) = ((#b(w)+1) mod m)} I am looking at a past test question which gives me the options m(m+1) 2m m^2 m^2+1 infinite However, i claim that its m, and I came up with an…
Abraham Murciano Benzadon
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Does order not matter in regular expressions?

I was looking at the question posed in this stackoverflow link (Regular expression for odd number of a's) for which it is asked to find the regular expression for strings that have odd number of a over Σ = {a,b}. The answer given by the top comment…
agreatkid
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PDA to accept language with more a's than b's and c's

My question is similar to this one. I was wondering if a PDA exists, that accepts any words containing a's, b's and c's in a random order, where the total amount of a's is higher than the amount of the b's and higher than the amount of c's, so for…
kepler
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DFA that contains 1101 as a substring

I have to draw a DFA that accepts set of all strings containing 1101 as a substring in it. I tried one by myself but wanted to make sure if it's correct but can't attach the image as I'm a new user. Thanks
Waqar Danish
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Confusion about the Kleene star

I have been struggling to understand one key property about the closure of two union'ed expressions. Basically what I need to know exactly how the Kleene star works. I.E If Regular Expression R = (0+1)* Does the expression have to evaluate to…
Gipjoe
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If a language (L) is recognized by an n-state NFA, can it also be recognized by a DFA with no more than 2^n states?

I'm thinking so, because the upper bound would be the 2^n, and given that these are both finite machines, the intersection for both the n-state NFA and the DFA with 2^n or less states will be valid. Am I wrong here?
John
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Finite automata to regular expression via state removal

I am trying to convert this finite automata to a regular expression using state removal. When removing a state, I know that I should look at all outgoing and incoming transitions, and make sure sure that all paths though the soon to be removed state…
pythonbeginner4556
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Construct a grammar that generates L = {a^p b^m c^n|n>=0, m>=0, p=m+n}

Construct a grammar that generates L: L = {a^p b^m c^n|n>=0, m>=0, p=m+n} Till now I have attempted this much: S->A A->aAb|B B->aBc|epsilon Is my grammar right?
Rachit Belwariar
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DFA - design a DFA that accepts all strings over {0,1} that contains at most two 00's and three 11's as substring

I am practicing my DFA and I came across this question that seems to be very complex. I tried splitting it up into two smaller questions and I have an answer but it doesn't look right to me. Can someone help me or at least give me some tips. They…
Gana
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How can I prove this language is regular?

I'm trying to prove if this language: L = { w={0,1}* | #0(w) % 3 = 0 } (number of 0's is divisble by 3) is regular using the pumping lemma, but I can't find a way to do it. All other examples I got, have a simple form or let's say a more defined…
mrklr
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How to remember NFA's choice on a certain computation?

I'm working on solving the question answered at this page but with different values at the table, my alphabet is {a,b,c} Words that have the same right- and left-associative product Currently I'm in the stage where I have drawn the DFA of the…
CSGuy
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