Questions tagged [kolmogorov-complexity]

The Kolmogorov complexity of a string s is equal to the length of the shortest program computing s and halting. Measures the lack of structure in a string.

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Can a Kolmogorov complexity oracle solve halting problem?

I can find https://www.nearly42.org/cstheory/halting_to_kolmogorov/ but the halting problem part is unrelated to proof that kolmogorov can't be solved(still that assume it solvable and output a longer ...
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Algorithmic information theory with stochastic algorithms?

Suppose we define a class of algorithms that is allowed to sample i.i.d. Bernoulli bitstrings of arbitrary length, and use these to generate outputs. If we are allowed to use algorithms like this, ...
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A property of Kolmogorov random strings

I am working on the following problem: Prove that, for all $k\in\mathbb N$, there exists $n\in\mathbb N$ so that every binary string $x\in\{0,1\}^{kn}$ with Kolmogorov complexity $K(x)$ at least $kn$ ...
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Expressivity of neural networks, how much information can be stored

I want to know whether a given neural network (with a finite number of nodes) is able to store all injective maps f: D -> C, where D has cardinality k and C has cardinality N (so the number of maps ...
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Turing machine that checks whether a given string is an output of a given machine and input

Is there a Turing machine such that, given a description $\langle M \rangle$ of a Turing machine $M$, an input $x$ and a string $y$, computes whether or not $y$ is the output of $M$ input $x$? My ...
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How many strings of length |w| are unrelated?

For sufficiently large |w|, how many of the 2^|w| strings of length |w| are entirely unrelated? A way to define this: two strings are unrelated if their joint Kolomogorov complexity is practically ...
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Kolmogorov-Complexity of strings in decidable languages

I just recently learned about Kolmogorov-Complexity and had an idea for giving an upper bound for strings in a decidable language. Is the following statement true? Say we have a recursive language. ...
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How to define enumeration of the set of finite state machines?

I want to write a function that takes N (maximum number of states) as a parameter, enumerates all possible finite state machines up to N states, and returns random FSM with a probability in proportion ...
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Computability of Kolmogorov Complexity of Turing-Incomplete language

I am trying to determine whether Kolmogorov complexity is computable for a specific language. I am certain this given language is not Turing-Complete. The language is defined as follows: $A;B \text{ - ...
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Kolmogorov complexity of a product of two numbers

In his book "Theoretical Computer Science", Juraj Hromkovic informally defines the Kolmogorov complexity $K(x)$ of a word $x$ consisting of zeros and ones as the binary length of the shortest Pascal ...
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Why don't prefix-free Turing machines suffer from complexity dips?

It's claimed in several texts on algorithmic complexity that prefix-free Turing machines are better for understanding randomness, at least in infinite sequences. In Nies' Computability and Randomness,...
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Is Kolmogorov-random nonsensical for small numbers?

The Wikipedia definition of Kolmogorov-random defines a string (usually of bits) as being random if and only if it is shorter than any computer program that can produce that string. Aren't nearly1 ...
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Computing the Kolmogorov complexity of a string

What would be the implications for complexity theory if you could compute the Kolmogorov complexity of a string generated by a psuedorandom generator?
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Kolmogorov Complexity of ​String Concatenation

For all bit strings $x$, $y$ and Kolmogorov complexity $K$, is $K(xy) > K(x)$?
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Is Kolmogorov Complexity Universal?

Is the Kolmogorov complexity of any piece of information with respect to a certain predefined encoding for all pieces of information, or can the encoding vary for each piece of information? ...
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How connected are information theory and algorithmic information theory?

In the book by Cover and Thomas on information theory, there is a chapter on algorithmic information theory (kolmogorov complexity and so forth). As far as I understand, algorithmic information ...
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Kolmogorov Complexity, struggle with equation

I am working on understanding Kolmogorov Complexity. I've been struggling with the following exercise for quite some time now and would appreciate any inputs. Show that there exists a constant $c$, ...
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How many “compressible” strings are there?

Let's say that a string of length $N$ is "compressible" iff its Kolmogorov complexity is less than $N$. To keep it simple, we can assume binary strings for this. It is easy to see that almost all ...
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On teaching Kolmogorov complexity with Python and the complexity of composed strings

The setting of this question is a bit long-winded, but please bear with me. This fall I will be lecturing a course on mathematical information theory, and on a few lectures we will be discussing ...
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How can I prove the languages of incompressible words is undecidable?

I have hard time understanding the proof by contradiction for the claim "$L=\{x : K(x) \ge |x| \}$" is undecidable ". The proof is as follows : M' = " On input $n$ Enumerate over all $n$-...
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Examples of exact computation of Kolmogorov complexity?

First question: It is known that Kolmogorov Complexity (KC) is not computable (systematically). I would like to know if there are any "real-world" examples-applications where the KC has been computed ...
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Range of values for Kolmogorov complexity

Let $n$ be a positive integer. Is it true that for all $1\leq i \leq n$ there exists a length $n$ binary string $w$ such that $K(w) = i$. Where $K(w)$ is the Kolmogorov complexity of $w$. For each ...
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Kolmogorov randomness for Pseudo random number generator

I am working on pseudo random number generation for one of my projects. My goal is to prove that the output is almost Kolmogorov Random since Kolmogorov complexity is uncomputable. So would appreciate ...
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What doest it mean: “computer is an intelligence amplifier”?

There is one example in Kolmogorov complexity books and related articles: Consider we have a monkey at a typewriter and a monkey at a computer keyboard. If the monkey types at random on a typewriter,...
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Computability of Kolmogorov complexity in total languages

It is well known that the Kolmogorov complexity is uncomputable in Turing-complete programming languages. However, what about total programming languages? For example, is the Kolmogorov complexity of ...
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How do you resolve this paradox with the invariance theorem?

The invariance theorem of kolmogorov complexity states that for two different languages with complexity functions $K_1$ and $K_2$, we have $$\exists c.\forall s. K_1(s) \le K_2(s) + c$$ Here is an ...
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Unrolling closures into SAT boolean formula

I need to verify some assertions about the minimalist Turing-complete language Jot. Many of the assertions I want to investigate are semi-deciable (co-recursively enumerable). So far it's been fairly ...
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Is there a hierarchy theory for time-bounded Kolmogorov complexity?

We know that there are languages in $DTIME(n^t)$ and not in $DTIME(n^s)$ for all $t>s$ due to simple diagonal arguments (i.e., the Time Hierarchy Theorem), but I'm wondering if there is any ...
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Solomonoff's theory of induction, Kolmogorov complexity and Bayesian Inference

My motivations for asking this question are philosophical in nature. I'm by no means a computer scientist though, and I feel as though this question should be answered by someone who is since it's one ...
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How can Kolmogorov complexity help me practically with measuring entropy?

A comment was made to me saying the following in relation to Kolmogorov complexity:- You're not the first to think non-computability = impractical or even useless. But it can be useful. In particular ...
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VC Dimension of A Set of Hypothesis

I am confused about what does a VC dimension of a set of hypothesis means. I have two hypothesis, say $H_1$ with VC dimension of $x$, and $H_2$ of VC dimension of $y$. Does this automatically mean ...
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Perturbative Kolmogorov Complexity Bounds

Are there any known bounds on the impact of changing (for example) one bit in a string on the resulting string's Kolmogorov Complexity? In mathematical terms, does the equation $|K(x) - K(x')|$ (with $...
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Kolmogorov complexity of a sequence of n bits with k ones

Let Program P be :"Generate, in lexicographic order, all sequences with k ones and n bit length; Of these sequences, print the ith sequence." Apparently the length of this program is $\log(n) + \log(\...
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Is there a universal metric of “size of a program”?

There is a universal metric of information: amount of bits. It's universal in the sense that if we write a piece of information in DNA (4-ary digits), we can simply multiply by 2-log-4 to get the ...
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Prove that A is non-regular using K-Complexity Non regularity theorem

Given $Y^A_{x,n}$= the nth string $y∈Σ^∗$ (in lex order) such that $xy∈A$ (if n such y exits). So what completes $x$ if adding $n$ such $y$'s brings us to an element in the set $A$ Given $A \subseteq ...
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Non Regularity proof using Kolmogorov Complexity (Li - Vitanyi Theorem)

When proving a language is non regular we can use Kolmogorov complexity. As far I know to do this we just have to use this satisfy the following conditions Given $Y^A_{x,n}$= the nth string $y∈Σ^∗$ (...
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Kolmogorov complexity of prefixes of computable sequences

Let the characteristic sequence of a set $A ⊆ \mathbb{Z^+}$ be the following infinite binary sequence: $$χ_A = b_1b_2b_3\ldots,$$ whose $n$th bit is 1 if $n ∈ A$ And 0 otherwise. Write $χ_{A,n}$ for ...
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Kolmogorov Complexity proving there exists a constant for when if two strings are equal length

When talking about kolmogorov complexity, I understand that it describes true randomness of given (for now) a string $x$, if we can describe x in less than the $|x|$ then its complexity is said to be ...
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Kolmogorov complexity of string concatenation

If $K(s)$ is the Kolmogorov complexity of the string $s \in \{0,1\}^*$, Can we prove (or disprove) the following statement: "Every string $s$ is a prefix of an incompressible string; i.e. for every ...
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Proof: Kolmogorov complexity of string concatenation

Does there exist a universal constant $c$ such that for any strings $x, y$, we have: $$K(xy)\leq K(x) + K(y) + c$$ where $K(\cdot)$ denotes the Kolmogorov Complexity of a binary string and $xy$ means ...
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United space-time complexity of finite strings

Let's consider bit string as a program for some computational model. If after $k$ steps program represented by number $n$ halts and outputs bit string $s$, then complexity of s is (n+1)*k. For example ...
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What is static complexity?

Definition : Kolmogorov complexity is a static complexity measure that captures the difficulty of describing a string. For example, the string consisting of three million zeroes can be described with ...
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How to calculate Kolmogorov Complexity if we have access to an Oracle for the HALT Problem

I try to solve the following exercise: We know that K (x), the complexity of Kolmogorov, is incomputable. Show how calculate it, if we have an oracle for the membership problem (or for the HALT ...
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What Good Is Kolmogorov Complexity Since It Is Relative?

Kolmogorov complexity is relative to a choice of Universal Turing Machine. Because of the Invariance Theorem, the difference in complexity assigned by two Universal Turing Machines is bounded by a ...
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Prefix complexity of x conditioned on prefix complexity of x

I wonder what is $K(x|K(x))$, $K$ denoting (Kolmogorov-Chaitin) prefix complexity. Naively, it looks like it should just be $K(x)+O(1)$. Is that right? The same question for plain Kolmogorov ...
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When is conditional Kolmogorov complexity zero?

It seems intuitive that conditional Kolmogorov complexity is only zero when the bitstrings are the same, and otherwise is greater than 0. I.e. if $b_1 = b_2$, then $K(b_1|b_2) = 0$, otherwise $K(b_1|...
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If a bitstring is compressible, is the minimal Kolmogorov sufficient statistic most likely large or small?

If a bitstring is incompressible, then its minimal Kolmogorov sufficient statistic (MKSS) is zero, since the bitstring is best represented by a structure function that enumerates bitstrings, and thus ...
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What do you call a set which has the following enumeration-related machine?

A set $S$ of natural numbers is Recursively Enumerable if there exists a Turing machine which enumerates them, i.e. given no input, outputs the elements of $S$ in increasing order (never halting if $...
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What is The correct terminology for expressing *this* notion of complexity

Say for example, I have an algorithm $Al_i$ that produces output from the set $S = \{s_i\}$ for problems from the set $P = \{p_i\}$, and another algorithm $Al_j$ that also produces output from the set ...
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What is an example of complex random string, in the Kolmogorov-Chatin sense?

Any string generated from a PRNG clearly has a very short description. You need the code for the random number generator, the seed, and then the number of times to iterate. So, it seems that all ...