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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number of dfa's that can be designed
Can we calculate the total number (i.e maximum no.) of dfa's that can be designed when the following constraints are put: |Q|=2{No. of states is 2},|Ɛ|=2{No. of alphabets} and |F|=1{No. of Final States} ?
Sharat Ainapur
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How to draw a DFA for given language?
Give a finite state diagram for a DFA that accepts any word in the language
L = {w | w ∈ {a, b}∗ and w alternates a’s and b’s and has an even number of b’s}.
My attempt: I am having problem on how to deal with the even part of b.
max
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Understanding epsilon closure algorithm pseudocode
The following pseudocode is from Introduction to Compiler Construction in a Java World book. This algorithm is supposed to output the epsilon closure of a set of a states of a nondeterministic finite machine (to convert it to a deterministic one…
Algo
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What is the minimum number of states to recognize this language?
Definition of a language L with alphabet {a} is as follows:
L= { a^{nk} | k > 0,n >0}.
There were four options to this question
k+1
n+1
2^(n+1)
2^(k+1)
k > 0, and n is a positive integer constant
Akshat Sharma
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Let Σ= {a}, assume language, L= { a^(2012.K) / K> 0}, what is minimum number of states needed in a DFA to recognize L
In my opinion it should be 2012 but I am not sure.Thanks for the help.
Akshat Sharma
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What is this DFA means?
There is a DFA.
But I don't know this DFA means.
I want to know this DFA's Regular expression and description
(Description like 'this automata accept suffix is 011)
Blue state is start state and red states are accept states.
Jihoon Yoon
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underscore in my alphabet for finite state automata table
I am tasked with a program that is a scanner. My alphabet is as follows:
all english letters (upper and lower), digits,
plus the extra character _ (underscore) & ws. Identifier begins with a letter and can
continue with any number of letters,…
c_sharp
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Questions and answer solving books on computer network and finite automata
I was looking for a problem and solutions books over the internet for data computer netwrok and Finite automata theory to enhance my problem solving skills, couldn't find out any one as i needed.
Do you help me here?
Thanks,
Arup Rakshit
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NFA to DFA Algorithm
I've read a text file of symbols, states and transitions and put it all in a table. It looks like this:
symbols a, b
states q1, q2, q3, q4
start state q4
final state q2, q3
transition state:
q4, epsilon, q1
q1, a, q2
q3, a, q3
q3, b, q1
I've read…
gingergeek
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Regular Expression | Automata Theory
does anyone know about regular expressions of the following languages:
the set of all strings starting with 000 and not ending 11
the set of all strings with odd string length and ending in 111
L6 is the set of all strings ending in 00 and…
Apriana
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2 answers
Deterministic finite automata uses
I know how a dfa works but the only thing I'm confused is about it's use.
I've seen it's several applications on the internet like it is used in Traffic lights, in parser etc. but what is the exact point where it is used?
Like if I want to design a…
explorer
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Is there a two state TG that accepts all the input strings from {a, b}* that are not in EVEN-EVEN?
I am new to the topic of finite automata and transition graphs. I had a quiz that asked that if there is a two-state TG that accepts all strings from {a,b}* that are not in EVEN-EVEN (language that have an even number of a's and even number of b's).…
Ibrahim
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What is the regular expression for the machine shown?
I'm wrestling with the problem and got 0*1+(00 U 01)* as the regular expression for the language that describes this machine. Is this correct? Or is there a better/simpler answer?
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2 answers
What is Subset Construction in Compiler design?
here is the algorithm : I am going through the aho,Ulman reference book on Compiler Construction, which explains the subset construction implementation algorithm for NFA to DFA conversion. The explanation there is very brief. I would like to have a…
RJSD3V
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How to draw a dfa for this language :L={ w | w has an even number of a’s and one or two b’s}
I tried this problem but i get stuck everytime because i am unable to satisfy the second condition for b. Someone give the right dfa diagram for the language.
Prajwal K
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