Questions tagged [church-turing-thesis]
For questions about the interpretation, extension and validity of the Church-Turing thesis, the hypothesis that states that a function is effectively calculable by a human if and only if the function is computable (on a Turing machine)
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Does Nondeterministic TM is a counterexample of Extended Church-Turing Thesis?
We know that Extended Church-Turing Thesis (or Cobham's thesis) states that any 'reasonable' model of computation can be equivalent to Turing Machine model in at most polynomial time overhead.
People ...
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2answers
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How do we define the term “computation” across models of computation?
How do we define the term computation / computable function generically across models of computation?
Beginning with the textbook definitions of: {Linz, Sipser and Kozen} for "computable function&...
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1answer
15 views
Question regarding notation of a language decidability
$1.\: A_{DFA} = \{\langle B, w \rangle \mid B \text{ is a } DFA \text{ that accepts input string } w \}$
$2.\:A_{DFA} = \{\langle B \rangle \mid B \text{ is a } DFA \text{ that accepts input string } ...
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1answer
40 views
Church-Turing Thesis - the mechanical model - the turing machine- its limits and its equivalence with a modern digital computer
Well in many texts and places I have seen a called statement, which claims it self to the famous "Church Turing Thesis".
I have seen many texts say that based on Church-Turing Thesis :
&...
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1answer
42 views
Computability of function composition
I have some problems to understand computability and hope you can help me.
In the lecture we had following problem:
Consider the three partial functions $f,g,h\colon N \to N$, where $f$ is computable ...
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2answers
57 views
The Church-Turing thesis and Hyper-computation
I am not a computer scientist and this is my first question.
This question is a question in layman terms and I also want the answer in layman terms.
When I searched hyper-computation. There was a list ...
4
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1answer
141 views
Kleene's Theorem and TMs
I wanted to know that based on Kleene's theorem (a language is regular iff some FSA recognizes it), does every regex have a TM (Turing machine) that halts on exactly the same language?
Is this ...
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1answer
104 views
Are there more Turing-unrecognizable languages than recognizable?
Say you generated a language by looking at the output of a lexicographic enumerator and flipping a coin for each string, adding it to the language on heads. What would be the chance of this language ...
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1answer
116 views
Halting problem for turing machines with one input
My question is:
Is there a simple construction similar to Turing's 'liar' program that shows that Turing machines plus a halting oracle cannot decide if a given Turing machine halts on all inputs.
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1answer
138 views
Computational power of a Turing Machine with infinite states
Consider a turing machine with infinite states. This machine is identical to a regular machine. Only that number of states could be infinite.
Does this machine has more computational power than a ...
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1answer
52 views
running RAM on a given input
I understand how RAM commands work but I am unable to understand how we use a given input string and find the output. For instance,
there's a Random Access Machine which has an input {0,1}*. The ...
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1answer
62 views
change turing machine to RAM
How can we convert a given Turing Machine into a Random Access Machine? I understand that we can use the transition function to come up with a sort of algorithm but how can we translate all of it into ...
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1answer
141 views
How to prove the language of all Turing Machines that accept an undecidable language is undecidable?
I want to prove that $L=\{\langle M \rangle |L(M)\text{ is undecidable}\}$ is undecidable
I am not sure about this. This is my try :
Suppose L is decidable. Let $E$ be the decider from $L$. Let $A$ be ...
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2answers
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Intuition for Church-Turing thesis for Turing machines
I can very clearly see "why" mu-recursion is a universal model of computation, i.e. why the Church-Turing thesis -- that any physically computable algorithm can be executed with mu-recursion ...
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1answer
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Is the languague L={<M>, M accepts a finite amount of words} decdidable?
Is $L=\{<M> | L(M) \ is \ finite\} $ decidable ? M is a TM.
I think its relative simple to proof with the theorem of rice. But I am interested in a solution which does not use the Rice theorem.
...
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2answers
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Equivalence between a TM and a changing TM
Let a changing TM be a TM which is not able to write the same symbol which is being read.
Formal: $M^*=(Q,\Sigma,\Gamma,\delta,q_{accept},q_{reject})$,$\delta(q,a)=(q^*,a^*,c),a \neq a^*$ with $q,q^...
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1answer
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About computable sets
Let TOT be the set of all Turing Machines that halt
on all inputs.
Find a computable set B of ordered triples such that:
TOT = {e : ($\forall$x)($\exists$y)[(e, x, y) $\in$ B]
This definition means ...
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4answers
553 views
To what extent is an x86 machine equivalent to a Turing Machine?
To what extent is the abstract model of computation specified by the x86 language Turing complete?
The above question is related to this question: Is C actually Turing-complete?
In theoretical ...
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2answers
57 views
There are functions with f (n) = f (2n) which can't be calculated
I have to proofe that there are functions defined by $f:\mathbb{N} \rightarrow \mathbb{N}, f(n)=f(2n), \forall n\in \mathbb{N}$, which are not-computable. However I'm not really sure about the correct ...
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2answers
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Why is nondeterminism physically not realizable?
Why it is so hard to make a nondeterministic computer? If such a device is physically realizable then would that be a counterexample to the extended Church-Turing thesis?
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1answer
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Are Turing unrecognizable and undecidable languages, recognized and decided by hyper computation?
Do the hyper computing machines/models that are supposed to be more powerful than Turing machines, capable of recognizing and deciding the languages that are not recognizable/decidable by Turing ...
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1answer
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Some questions about the Computability of Turing Machines
I'm learning for a test and I have some important questions about Computability of deterministic and non deterministic Turing Machines.
Consider we have the partial functions $f,g,h,t: \mathbb{N} \...
3
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1answer
136 views
Can current quantum computers decide languages that Turing Machines cannot?
I am currently learning Computing Theory at university, and we were on the topic of Turing-Decidability, Recognizability, etc. Showing that a problem is undecidable with Turing machines due to ...
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0answers
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Universal Turing Machine run on Universal Turing Machine
I am curious, what happens if we run Universal Turing Machine on itself?
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2answers
119 views
Turing machine where the next step is determined by the state and the symbols up to the read/write head
Given a modified type of turning machine where
$\delta = Q\times \Gamma^* \implies Q\times \Gamma \times \{L,R\}$
where the next step of the machine is determined by the current state and whatever ...
0
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2answers
130 views
Are Linear Bounded Automatons Turing Complete?
Linear Bounded Automatons are just Turing Machines with finite tape, instead of infinite tape.
But this causes them to not be Turing Complete? Why?
2
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1answer
563 views
How to come up with a language that is recognizable but not co-recognizable?
Forming a language that is recognizable but not co-recognizable. I'm having trouble coming up with a language with these properties. A recognizable language is a language $A \subseteq \Sigma^*$ iff $A ...
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2answers
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Does this article imply that Turing-Computability is not the same as “effectively computable”?
I've stumbled across this article. It says that there is a problem that only Quantum Computers can solve.
In my understanding, this should mean, intuitively, that this problem is "effectively ...
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1answer
187 views
Is turing completeness related to recursive enumerable languages?
I recently came across this term "Turing complete" in my study of morphogenesis models. When I looked up, it said that a turing complete machine can simulate a universal turing machine.
When I ...
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1answer
79 views
Empirical evidence for the Church-Turing thesis in other disciplines
I am aware of the fact that, since the concept of "effectively calculable function" is not rigorous or formally definable, the Church-Turing thesis may not be proven by symbolic or formal reasoning ...
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2answers
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Would any continuous model of the universe have/be based on hypercomputational laws?
I've read that when Turing-Church thesis is applied to the universe and physics, one of the three interpretations that we can use and is defended by some important physicists is that:
"The universe ...
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0answers
103 views
Church-Turing thesis and hypercomputation?
The Church-Turing is a hypothesis about the nature of computable functions. It states that a function on the natural numbers is computable by a human being following an algorithm, ignoring resource ...
0
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1answer
70 views
The Church-Turing Thesis (Hello World tester) contradiction and randomized algorithms
The Church-Turing thesis proves that there is no algorithm (or program) $H$ that says whether a program $P$ written in a language, say $C$, on an input $I$ outputs the sentence ...
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3answers
278 views
Is a Turing machine too strong of a model to model physical computation?
I've heard many times people debate the possibility of a real world computation that is impossible for a Turing machine, especially in the context of a human mind. Implying that the Church-Turing ...
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1answer
75 views
Isn't the given characterisation of recursively enumerable subsets of the class of all recursively enumerable languages?
$S$ is a subset of the class of all recursively enumerable languages over some finite symbols then $S$ is recursively enumerable iff
If $L$ is in $S$ and $L'$ is a language such that $L ⊆ L'$ and $L'$...
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2answers
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Do any programming languages use general recursive functions as their basis?
This is a naïve and, therefore, possibly malformed question, so apologies in advance!
My view is that a Turing Machine can be seen as the computational basis for procedural/imperative programming ...
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1answer
37 views
Comparing turing based programming languages
According to Turing thesis, Can we say all programming languages that support turing machine like C have same power for solving problems and performing algorithms? In other words is there any ...
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0answers
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The evolution of the term “recursive” from Goedel to Church to present day
I'm currently studying some of the history of computation / computability, in the early days known as recursion theory.
I see Goedel's definition of recursive functions seems significant in his paper,...
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0answers
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The rules for Turing Machine ,equivalence?
We have regular expression for DFA and NFA, at the same time, we have CFG for PDAs, What do we have for Turing Machine? If this questions is too obvious, please points me some reading, I am just ...
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5answers
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Turing machine + time dilation = solve the halting problem?
There are relativistic spacetimes (e.g. M-H spacetimes; see Hogarth 1994) where a worldline of infinite duration can be contained in the past of a finite observer. This means that a normal observer ...
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2answers
570 views
prove A is co-re
Working on some cs theory and solving a problem on computationally [=recursively] enumerable languages:
A language $A\subseteq \{0,1\}^*$ is co-c.e. if and only if there is a decidable language
...
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1answer
112 views
It is possible to write any program (i.e. Turing complete) with just one single expression?
So I'm currently taking discrete math II at my university and I came across a somewhat philosophical question (so I apologize if this is question is hard to answer precisely) of whether mathematicians ...
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2answers
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Church-Turing Thesis and computational power of neural networks
The Church-Turing thesis states that everything that can physically be computed, can be computed on a Turing Machine.
The paper
"Analog computation via neural networks" (Siegelmannn and Sontag, ...
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1answer
326 views
The Church-Turing-Thesis in proofs
Currently I'm trying to understand a proof of the statement:
"A language is semi-decidable if and only if some enumerator enumerates it."
that we did in my lecture. One direction of the proof goes ...
2
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1answer
175 views
weak Church-Turing thesis
(weak) Church-Turing thesis states every physically realizable computation device can be simulated by a Turing machine (not necessarily efficiently).
(1) Then Does any model that is not physically ...
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3answers
273 views
Does computability according to Church-Turing thesis include side effects?
To my understanding:
The Church-Turing thesis means that one could theoretically compute anything that can be computed using either a Turing Machine or the Lambda Calculus.
The Lambda Calculus is ...
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2answers
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Is a physical process with unbounded input Turing equivalent?
Church-Turing thesis states that any effectively computable process is computable by a TM. Let's assume for now that it means that every physical machine is computable by a TM. Let's call it A.
Now ...
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4answers
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Can every self-modifying algorithm be modelled by a non-selfmodifying algorithm?
If we have any arbitrary computer program that can modify its instructions, is it possible to simulate that program with a program that cannot modify its instructions?
Edit:
I am new to ...
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0answers
66 views
Canonical definition of suitable encoding
I've had several Computer Science courses and, from what I recall, I've never been given a rigorous definition of suitable encoding. Definitions always tend to use effective method or some synonym to ...
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1answer
181 views
Church-Turing and physical PDEs
When I read about the Church-Turing thesis it seems to be a common claim that "physical reality is Turing-computable." What is the basis for this claim? Are there any theoretical results along these ...
