Stack Overflow
Stack Overflow

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".

692 questions
0
votes
1 answer

BNF Grammar Derivation

I want to apply rules of BNF Grammar to produce derivation for : a_Num
Vaibhav Jain
  • 33,887
  • 46
  • 110
  • 163
0
votes
0 answers

Formal Language syntax

Here is the question: Show that: L = {0m1n, m > 1, n > 1, n < m } , where m & n are superscripts is not regular. I am not sure what superscripts mean in this situation? Does it mean something like this: 0^5 = 00000 or 1^7 = 1111111 P.S. How can I…
Matt Hintzke
  • 7,744
  • 16
  • 55
  • 113
0
votes
1 answer

Pushdown Automata definition

I am quite confused about formal description of PDA (push down automata) If we write down L(M), this means that PDA M recognizes language L, correct ? then , L(M)* means that PDA M recognizes that L* right ? but what is the L* means ? how PDA can…
Sherry W. Birkin
  • 11
  • 1
  • 3
0
votes
2 answers

Is null string allowed for w, if "w ∈ {a, b}*"?

If L is a language defined by : L = { awa | w ∈ {a, b}* }, is aa a string of the language L? (notice that w is being null string here)
batman
  • 5,022
  • 11
  • 52
  • 82
0
votes
1 answer

Why is this not CFG?

Though this is a repitition of this, I talking in terms of designing a PDA. Now, I know I'm wrong, because this is a well publicised example, but where did I go wrong in the PDA design below? I want to accept language {a^n b^n c^n: n>=0} I push two…
nimbudew
  • 958
  • 11
  • 28
0
votes
1 answer

How to solve δ(A,01) for this DFA?

Consider the DFA : What will be δ(A,01) equal to ? options: A) {D} B) {C,D} C) {B,C,D} D) {A,B,C,D} The correct answer is option B) but I don't get how. Please some one explain me the steps to solve it and also in general how do…
Brite Roy
  • 425
  • 3
  • 9
  • 28
0
votes
2 answers

FInite automata to regular expression clarification

Can you check on this: https://dl.dropbox.com/u/25439537/finite%20automata.png This is a checked homework, so don't worry. I just want to clarify whether my answer is correct or not, because it is marked by my teacher as incorrect. My answer is…
user1846682
  • 35
  • 4
0
votes
1 answer

Designing nfa that accepts couple of strings

I need help designing an nfa that accepts the words "hello","hello world" and "stay together" the alphabet includes the english alphabet,numbers and symbols. I need help getting started. Anyone has any suggestions?
Israel Rodriguez
  • 209
  • 2
  • 8
  • 15
0
votes
1 answer

Debugging or mapping out a large state machine?

I'm trying to debug a chunk of code that's mostly a straightforward 16-state state machine, although there are some cases where the transitions are not very simple (the data the state changes operate on are about 200 bytes of data in a couple C++…
ProdigySim
  • 2,825
  • 1
  • 21
  • 17
0
votes
1 answer

how to correct a slightly incorrect DFA, for a given correct input string?

I wrote a program which can generate DFAs. But the DFAs are slightly incorrect. That is, sometimes they can't accept the correct strings. My question is: is there any algorithm can correct the DFAs, so that they can accept the given correct…
JackWM
  • 10,085
  • 22
  • 65
  • 92
0
votes
1 answer

How can I construct a finite automaton for even decimal numbers?

I have to do this exercise and am completely stumped as to how. I've constructed some FA's before, but using binary numbers. How can I do this but for even decimal numbers?
Tino
  • 91
  • 2
  • 8
0
votes
2 answers

Where can I find sample automata and turing machines?

I'm studying for an automata test on a course that's heavily based on jflap. Trouble is we don't have much documentation and the sample automata that I've found on jlap like this and this, are insufficient to prepare for the upcoming test. Where…
andandandand
  • 21,946
  • 60
  • 170
  • 271
0
votes
2 answers

Ternary Numbers, regex

I'm looking for some regex/automata help. I'm limited to + or the Kleene Star. Parsing through a string representing a ternary number (like binary, just 3), I need to be able to know if the result is 1-less than a multiple of 4. So, for example 120…
K-man
  • 353
  • 1
  • 13
-1
votes
0 answers

how to prove that the perfect shuffle of two regular languages is regular

This exercise is taken from book "introduction to computability theory" of Michael Sisper Given the languages A and B, the perfect shuffle of A and B is the language {w | w = a1b1a2b2 . . . akbk, where a1a2 . . . ak ∈ A and b1b2 . . . bk ∈ B, each…
Davide Cecconi
  • 1
  • 1
-1
votes
1 answer

Representing regular expressions with DFA state diagrams

I have these regular expressions: a) 0(10)* b) a(b+c+d) c) b*(aa*b*+ε) I created these state diagrams for them: Are they correct?
Marnie
  • 21
  • 1
1 2 3
…
46 47