A finite automaton (FA) is a mathematical description of an algorithm capable of parsing regular languages. FAs have no external memory, and as such can only take into account a fixed number of previous symbols when processing strings. A deterministic FA (DFAs) is one for which there is only ever one legal transition between states; nondeterministic FAs can be transformed into equivalent DFAs. FAs are the weakest of the commonly-defined automata.
Questions tagged [finite-automata]
585 questions
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Is it possible to have more than one minimal DFA 's for a regular language?
If we create two DFA's for a language L say DFA A and DFA B. Then, after minimising the DFA's we get their corresponding equivalent minimal DFA's . Is It always the case that both minimal DFA's have same number of states?
I designed 2 DFAs for a…
Digvi_sp
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Writing the production rules of this finite state machine
Consider the following state diagram which accepts the alphabet {0,1} and accepts if the input string has two consecutive 0's or 1's:
01001 --> Accept
101 --> Reject
How would I write the production rules to show this? Is it just:
D -> C0 | B1 |…
David542
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Why doesn't {a^nb^n | n >= 0} follow regular language closure properties?
Using the pumping lemma, we can prove that {a^nb^n | n >= 0}, but what is not clear is the following.
{a^n | n >= 0} is regular by itself and so is {b^n | n >= 0}, and if I am not mistaken, regular languages are closed under concatenation, so why…
user19187727
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L={aʲbᵏaˡ | l = j * k} Context free? Recursive?
I have to classify the language L={aˆjbˆkaˆl | l = j * k}.
I applied the pumping lemma for CFL and think that it is not context free. However, to prove that it is in fact recursive or recursively enumerable, would I have to be able to construct a…
nTn
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Draw NFA for regular language
Here I found a example for a regular language.
L = { a^n | n>=2 } is regular. Clearly, we can draw a finite automaton with 3 states.
I was asking myself how this graph would look like. If I choose n=11, this means, that the language contains all…
Johnny
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NFA that does not accept strings ending "101"
What is the NFA that does not accept strings ending "101"?
Km Shrikanth
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Conversion of RE to FSA without ε
i have a reguler expresion
10+(0+11)*1
how to change the reguler expression to Finite State Automata ?
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In determinstic finite automata is there any possibility that every state is final state?
Is there any limit that final states should not more than some number(2,3,...) ?
Subhan Khaliq
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Designing a DFA
I want to design a DFA for the following language after fixing ambiguity.
I thought and tried a lot but couldn't get a proper answer.
S->aA|aB|lambda
A->aA|aS
B->bB|aB|b
Davood
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Is this correct NFA graph?
Task: Build NFA from a given regular expression.
I decided to push some of my old programs to GitHub. Specifically problems regarding Theory of formal languages. After testing code I had this result and I can't really tell if this a wrong or correct…
Edwin
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How to determine which language is simpler
The following language is the complement of a simpler language.
Construct a DFA for the simpler language and then use it to give the state diagram of a DFA for the given language where Σ = {a,b}.
L={ w : w does not contain the substring baba}.
I…
nmorsi
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Give context-free grammars that generate the following language
Give context-free grammars that generate the following language.
In all parts the alphabet ∑ is {x,s}.
{w| w starts and ends with the different symbols}
Muhammad Shahid Khan Afridi
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4 answers
An FA that accepts all binary strings with an even number of 0's and the number of 1's is a multiple of 3
This question is directly from Chapter 1 exercises of Introducing the Theory of Computation by Wayne Goddard (Question 1.17).
Initially I thought of creating two separate DFAs one for ensuring the number of 0's in the input is even and another for…
JungleJeem
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Every regular language is finite | True or False?
I tried to solve it using L=a*as anti-example, but it seems wrong.
{0, a, aa, ...} has to do with the number of strings
any suggestions?
Qehu
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