Questions tagged [enumeration]

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5
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1answer
77 views

Generate cut $(A,B)$ in edge-colored graph $(V,E_1 \cup E_2)$ such that there are more red than white crossings, i.e $|E_1(A,B)| > |E_2(A,B)|$

Let $G=(V,E)$ be graph. Recall that a cut of $G$ is (or can uniquely be identified with) a pair $(A,B)$ of nonempty subsets of $V$ which partition it. Given a cut $(A,B)$, let $E(A,B) := \{(a,b) \in ...
0
votes
0answers
105 views

Can you diagnolize without mentioning simulation?

Are there any known diagonalization proofs, of a language not being in some complexity class, which do not explicitly mention simulation? The standard diagnolization argument goes: here is a list of ...
3
votes
0answers
83 views

Are there enumerations of machines for all languages in 𝑃 such that there exists a simulator that can efficiently run all the machines enumerated?

From Kozen INDEXINGS OF SUBRECURSIVE CLASSES: "the class of polynomial time computable functions is often indexed by Turing machines with polynomial time counters.... The collection of all (...
8
votes
1answer
337 views

Can we efficiently enumerate the words accepted by a DFA by order of increasing weight?

Fix a deterministic finite automaton $A$ defining a regular language on the alphabet $\Sigma = \{0, 1\}$, and call the (Hamming) weight of a word $w \in \Sigma^*$ its number of $1$'s. Given a length $...
2
votes
0answers
42 views

The number of rooted ordered trees of max-out degree $k$

An ordered tree (also known as ordinal tree and plane tree) is a rooted tree in which the children of each node are ordered. It is known that the number of the ordered tree with $n$ edges is the $n$'...
1
vote
0answers
71 views

Complexity of enumerating over promise problems and circuits?

Given an enumeration over all Turing Machine which run with increasing length, is there a ``complexity class'' which describes the complexity of determining whether a given TM satisfies the promise ...
4
votes
2answers
844 views

Enumerating decidable languages

[The assumption in this question is wrong. It is possible to enumerate exactly the decidable languages with semideciders.] Lets say we have a TM $M_E$ enumerator that writes out codes of TM's on a ...
12
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0answers
287 views

Reference request: exponential growth rates of subsequence-closed languages are integers

This question is migrated from MathOverflow, where it did not receive any answers a year ago. For a language $L$ over the finite alphabet $\Sigma$, let $L_n$ denote the set of words in $L$ of length $...
4
votes
2answers
359 views

About the decidability of sets enumerated in non decreasing order

It is well known that a set of numbers enumerable in nondecreasing order is decidable. However, the typical proof, by cases on the finiteness of the enumerated set, is not constructive. In general, it ...
2
votes
1answer
157 views

Definition and Computational Model of EnumP

Valiant [1] defined the $P$-enumerable problem in which he used the Counting Turing Machine Model: A counting Turing machine is a standard nondeterministic TM with an auxiliary output device that (...