Stack Overflow
Stack Overflow

Questions tagged [turing-machines]

A Turing machine is an idealized model of computation consisting of a finite-state control, an infinite tape holding information, and a read head positioned somewhere over the tape. Turing machines are used in computability theory to reason about the limits of computation, to provide a formal definition for an algorithm, and to provide formal models for nondeterminism.

Wiki

A Turing machine is a device that manipulates symbols on a strip of tape according to a table of rules. Despite its simplicity, a Turing machine can be adapted to simulate the logic of any computer algorithm, and is particularly useful in explaining the functions of a CPU inside a computer.

Turing machines are not physical objects but mathematical ones. A Turing machine is a kind of state machine. At any time the machine is in any one of a finite number of states. Instructions for a Turing machine consist in specified conditions under which the machine will transition between one state and another.

The tape is used to store data. In addition, it can also store a series of transitions (a small programs) and thus, the head can run sub-programs. By analogy with modern computers, the tape is the memory and the head is the microprocessor.

Tag usage

The tag can be used for programming related problems in implementing features of a turing machine. The tag can also be used for algorithmic problems related to turing machine. Try to avoid theoretical and research based questions on Stack Overflow.

Please note https://cstheory.stackexchange.com is another stack exchange website which you can use to ask theoretical and conceptual problems with tag

Source

487 questions
0
votes
1 answer

Turing Machine Design

I recently encountered the following problem: Give a Turing machine diagram for a Turing machine that on input a string x ∈ {0, 1}∗ halts (accepts) with its head on the left end of the tape containing the string x′ ∈ {0, 1}∗ at the left end (and…
Ian
  • 3,605
  • 4
  • 31
  • 66
0
votes
1 answer

My copy loop does not end. Turing Machine

I am trying to write a set of rules that copies a set of ticks, however long one space next to the original set, I have a loop which does so, however it does not stop and continues ahead and breaks the copied…
James
  • 75
  • 1
  • 2
  • 6
0
votes
0 answers

Volume complexities of multihead Turing Machines

I'm trying to prove that for every multihead Turing machine X, there is a multihead Turing machine y such that for any input string z, we have volume(X, z) = Θ(Y(z)) and volume(Y,z) = Θ(Y(z)). In other words, the three values are all equal up to a…
Telo Springs
  • 45
  • 1
  • 12
0
votes
2 answers

Why would a Scripting language be made 'purposefully Turing non-complete'?

So, I was reading about Bitcoin Script on their official documentation and found this line: "Script is simple, stack-based, and processed from left to right. It is purposefully not Turing-complete, with no loops." I tried to reason hard but couldn't…
Anoop Dixith
  • 633
  • 2
  • 8
  • 20
0
votes
1 answer

Turing Machine Binary Counter

I decided for practice that I would create a binary counter simulating the methodology of a Turing Machine. To be specific, I plan to emulate the first example from this:…
Telo Springs
  • 45
  • 1
  • 12
0
votes
1 answer

How would you design a one-tape, two-head TM for checking tautonyms?

I have to figure out if this language L = { ww | w {0,1}*} is decidable by a Turing machine. The TM has 1 tape and 2 heads/pointers. The input string is finite. Any suggestions on how to solve it ? The way I see it, if I know the length of the…
Ben
  • 3
  • 2
0
votes
4 answers

why there can't be a program that checks another program

I am trying to find the logical alan turing explanation why there can't be a program that checks another programs. I remember we learned in on the computation course but now i just can't find the solution , and i need to explain it to some one at…
Night Walker
  • 20,638
  • 52
  • 151
  • 228
0
votes
1 answer

How can I show reduction from every language in RE to HP

L is considered to be Hard-RE if for every L' in RE, there is a reduction from L' to L (L'<=L) L is considered to be Complete-RE if L id Hard-RE and also L is in RE. How can I prove that HP is complete-RE? i will need to show reduction from every…
Ohad
  • 1,563
  • 2
  • 20
  • 44
0
votes
0 answers

Showing turing machines exist for the following

I'm struggling to understand a question I've been given. The question asks: Let A be a boolean formula in n variables. There are 2^n different combinations of assigning values to the variables. Consider the problem of deciding whether (strictly)…
Andrew Brick
  • 276
  • 2
  • 4
  • 18
0
votes
2 answers

How do I find largest subsequence in turing?

In college I came across this and I couldn't seem to find an answer for it yet (it's not a homework, just a riddle). Let's say you have input in Turing machine: 01001101 (8 bit sequence) How do you count the largest subsequence of ones in such an…
carpenter
  • 251
  • 2
  • 11
0
votes
1 answer

Turing machine that goes left on first symbol

I have a turing machine with transitions given by the following table I'm inputting the string aaaa. So if I look at the first symbol "a" in state A, it says to replace it with an X, go into state B, and move Left. This is where I'm confused. How…
user3000731
  • 93
  • 2
  • 11
0
votes
1 answer

Some NFA & REGULAR LANGUAGE & Equivalences

I read some note about Automaton Course. i see this note, that following all is the same. but i think the L(g) is not equal to NFA and regular expression. anyone could help me with defining the language of this figures (nfa, regular expression and…
user4012783
0
votes
1 answer

Challenge on Alphabet and Formal Grammar and Language

We know set A is countable if A is finite or in a one-to-one mapping to natural numbers. Suppose ALPH be an arbitrary finite alphabet. I summarize my inference: a) Each arbitrary Language on ALPH is Countable. (I think this is True) b) the set of…
user4110176
0
votes
1 answer

Turing Machine support

I have a language: (XF*X|F)* over the alphabet: {X,F} How can I get/design a Turing machine to recognize that language? Any guidance or advice would be much appreciated
user3706271
  • 19
  • 3
0
votes
1 answer

How do I prove that the given language is not recognizable

Given the following language: Lf = { p(m) | The language of M is finite } Is Lf recognizable? if not, prove using reduction. Otherwise, build a NDTM which recognizes it. I'm kinda sure that Lf can not be recognized but I ain't sure how to prove…
Rouki
  • 2,239
  • 1
  • 24
  • 41
1 2 3
…
32 33