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48
votes
7answers
3k views

For which problems in P is it easier to verify the result than to find it?

For (search versions) of NP-complete problems, verifying a solution is clearly easier than finding it, since the verification can be done in polynomial time, while finding a witness takes (probably) ...
6
votes
2answers
198 views

FSM transducer sequential composition decidability

this is a followup/ sequel to this recent question which was answered, this one presumably significantly harder. consider a deterministic FSM transducer $F$ and its mapping $F(x)$ of an input word ...
1
vote
0answers
35 views

Current review on polygon partition problems

Mark Keil(1) provides an extensive survey of polygon partitioning and polygon covering alrogithms. This survey was written in 2000. Is there a more recent survey on this topic?
10
votes
1answer
194 views

Is it decidable whether the output length of a transducer is bounded by the input length?

The transducers considered here are those Wikipedia calls finite state transducers. The behavior of a transducer $T$, that is, the relation it computes, is written $[T]$: a word $y$ is an output for ...
2
votes
0answers
77 views

Extended version of the paper “Consistent Hashing and Random Trees” with proofs

I've been reading the following paper: David Karger, Eric Lehman, Tom Leighton, Rina Panigrahy, Mathew Levine, Daniel Lewin, "Consistent Hashing and Random Trees: Distributed Caching Protocols for ...
3
votes
0answers
132 views

Why can't we have superlinear bounds on Boolean circuit size for an explicit function?

I am interested about the minimal size (number of gates) of a family of circuits (with negation) over a complete Boolean basis (with fanin 2) that computes some explicit Boolean function. (In other ...
1
vote
0answers
58 views

Looking for reference proving polynomial-time bounds for A* search under specific conditions

In the textbook "Artificial Intelligence - A Modern Approach" (Russel, Norvig), it mentions that a sufficient criteria for the A* search algorithm to complete in polynomial time is for the heuristic ...
5
votes
1answer
138 views

Generating uniform integers in a range from a random generator with another range

Let $p$ and $q$ be two positive integers. I have an oracle that can generate a uniform integer in $\{1, \ldots, p\}$, the integers thus produced being independent across oracle calls. My goal is to ...
9
votes
2answers
201 views

Matrix vector multiplication algorithm using minimal number of additions

Consider the following problem: Given a matrix $M$ we want to optimize the number of additions in the multiplication algorithm for computing $v \mapsto Mv$. I find this problem interesting ...
20
votes
3answers
549 views

What are the relationships between those hypotheses in Fine-Grained Complexity Theory?

Complexity theory, through such concepts as NP-completeness, distinguishes between computational problems that have relatively efficient solutions and those that are intractable. "Fine-grained" ...
6
votes
2answers
265 views

Algorithm for finding heavy hitters in a weighted stream

The problem of finding heavy hitters in a stream is defined as follows: given a $N$ sized stream of elements, return a set $\mathcal D$, such that every item which arrived at least $N\theta$ times ...
0
votes
0answers
48 views

English translation of a paper by Dobrushin & Ortjukov

I'm looking for an English version of Dobrushin and Ortjukov, "An upper bound on the redundancy of the self-correcting schemes built on unreliable elements" I managed to find the Russian version ...
20
votes
2answers
2k views

Is it decidable to determine if a given shape can tile the plane?

I know that it is undecidable to determine if a set of tiles can tile the plane, a result of Berger using Wang tiles. My question is whether it is also known to be undecidable to determine if a single ...
9
votes
1answer
235 views

What is worst case complexity of number field sieve?

Given composite $N\in\Bbb N$ general number field sieve is best known factorization algorithm for integer factorization of $N$. It is a randomized algorithm and we get an expected complexity of ...
21
votes
1answer
408 views

Is it still open to determine the complexity of computing the treewidth of planar graphs?

For a constant $k \in \mathbb{N}$, one can determine in linear time, given an input graph $G$, whether its treewidth is $\leq k$. However, when both $k$ and $G$ are given as input, the problem is ...
2
votes
0answers
152 views

Is counting the words in a finite regular language #P-complete?

Almost the exact same question was asked here, but nobody proved or cited its #P-completeness! I found this question because I proved it is #P-complete (proof below), and the proof was trivial, but I ...
6
votes
8answers
1k views

Is it a Known Concept to Compute an Algorithm Once and Re-Interpret Answer for Different Inputs

I recently came across a strange concept and was wondering if this was a known / named concept in the realm of CS. The concept is that you evaluate some computation or logical circuit that takes in N ...
7
votes
3answers
238 views

Is there a theory of computation that takes failure and decay of the computation substrate into account?

There are obvious differences between a Turing machine and a real computer. Not only is the latter finite in size, it is also prone to failures and it is made from decaying matter. The kind of ...
2
votes
0answers
54 views

Minkowski decomposition of lattice point cloud

Given two point clouds $A,B\subset\mathbb Z^d$, let $A\oplus B$ be their Minkowski sum, defined as the set $\{ a + b : a\in A, b\in B \}$. Is there any known result for the following problem? ...
6
votes
2answers
132 views

Deciding functionality of transducers over infinite words

Given a finite state transducer defining a rational relation over infinite words, it is known to be decidable whether or not the relation is a function, i.e. whether each infinite input word is ...
19
votes
3answers
2k views

Who introduced nondeterministic computation?

I have two historical questions: Who first described nondeterministic computation? I know that Cook described NP-complete problems, and that Edmonds proposed that P algorithms are "efficient" ...
3
votes
1answer
128 views

Maximum size-k cut

Here's my problem, Problem: Given a weighted undirected graph $G=(V,E,w)$ with weight function $w:E\rightarrow\mathbb{R}$ and an integer $k$, find a cut $S$ of graph $G$ such that $|S| \leq k$ and ...
7
votes
2answers
420 views

Communication complexity problems with linear distance

Are there any known (non-trivial) randomized communication complexity lower bounds for natural gap problems in which the 1-inputs are linearly far from the 0-inputs? That is, partial functions ...
4
votes
0answers
187 views

What would a PDA be with a queue instead of a stack?

A while ago it occurred to me that the stack data model in a push-down automaton could be exchanged for a queue or deque model. I've explored this a bit as a pet project and it looks like an automaton ...
15
votes
1answer
385 views

Reference for mixed graph acyclicity testing algorithm?

A mixed graph is a graph that may have both directed and undirected edges. Its underlying undirected graph is obtained by forgetting the orientations of the directed edges, and in the other direction ...
13
votes
1answer
681 views

Permutations with forbidden subsequences

Let $[n]$ denote the set $\{1,...,n\}$ and C(n,k) denote the set of all $k$-combinations of elements from $[n]$ without repetition. Let $p= p_1p_2...p_k$ be a $k$-tuple in $C(n,k)$. We say that a ...
2
votes
0answers
32 views

Reference for randomized GMD decoding

The GMD decoder is an algorithm for decoding concatenated codes up to half their minimal distance. The standard presentation of this algorithm usually proceeds in two steps: First, one shows a ...
8
votes
0answers
197 views

Knot Recognition as a Proof of Work System

Currently bitcoin has a proof of work (PoW) system using SHA256. Other hash functions use a proof of work system use graphs, partial hash function inversion. Is it possible to use a Decision problem ...
5
votes
1answer
97 views

Survivable networks, directed case

I have been working on a project that turns out to be a special case of the directed version of the survivable network problem. Iterative rounding gives a 2-approximation of the undirected case. I'm ...
11
votes
1answer
204 views

L/P/PSpace vs P/NP

in 1979 Hopcroft/ Ullman wrote that L ⊆ P ⊆ NP ⊆ PSpace is known but L ⊊ PSpace is the only proper (& trivial) containment known although all are conjectured to be proper containments, and "where ...
1
vote
0answers
67 views

Runtime of Gomory's Cutting Plane Algorithm

I read in several sources that the use of Gomory's cuts exclusively in Integer Programming was shown to be inefficient in practice when Gomory had created them. But later down the line they were shown ...
7
votes
1answer
168 views

Limited number of variable occurrences in 1-in-3 SAT

Is there a known result on complexity class of 1-in-3-SAT with restricted number of variable occurrences? I've come up with the following parsimonious reduction with Peter Nightingale, but I want ...
3
votes
2answers
136 views

Is this covering problem NP-hard?

Given a rectangular region $R$ and a set $D$ of $n$ disks such that the union of all disks in $D$ cover the entire rectangular region $R$, the objective is to find the minimum cardinality set $D'$ ...
9
votes
2answers
286 views

Number of Automorphisms of a graph for graph isomorphism

Let $G$ and $H$ be two $r$-regular connected graphs of size $n$. Let $A$ be the set of permutations $P$ such that $PGP^{-1}=H$. If $G=H$ then $A$ is the set of automorphisms of $G$. What is the ...
3
votes
0answers
44 views

Substitution in Resolution Proofs

Let $F = C_1 \wedge C_2\; \wedge ... \wedge\; C_m$ be a unsatisfiable $k$-CNF on variables $x_1,...,x_n$, where $k$ is constant. Let $x_j\rightarrow x_j^1\wedge x_j^2$ be a substitution that replaces ...
2
votes
0answers
132 views

Construction of a graph which has regular subgraphs at each iteration of a recursive process

I am studying Graph Isomorphism and also trying to figure out the complexity of a certain class of graph. The graph I am studying at the moment is described below Description : $G$ is a $r$ regular ...
-2
votes
1answer
85 views

what can be said about complexity of “typical” supercomputing programs/ applications? any NP hard?

supercomputers have risen dramatically in their computational powers last few decades due to Moore's law & also increasing parallelism technology in hardware and software. many different types of ...
2
votes
0answers
74 views

Variant of set cover problem with symmetric difference instead of union? [duplicate]

I am wondering if this problem has been studied, and in particular if there is an algorithm for it. Consider a universe $\mathcal U$ and a set $A \subseteq U$, and a family of sets $\mathcal F ...
6
votes
1answer
118 views

A bounded-independence variant of the Berry-Esseen theorem

I came across a presentation by Ryan O'Donnell regarding invariance principles. After proving the Berry-Esseen theorem, there is a slide that discusses extensions of the theorem and one that is ...
4
votes
0answers
85 views

Random Sampling Threshold to Get a Connected Induced Subgraph

Working on network design this summer I have come across certain applications that have inspired me to ask the following question: Given an undirected connected graph $G=(V,E)$ what is the minimum ...
1
vote
0answers
73 views

“conservative approximate Set Cover”?

We are given a lattice graph $L$, embedded on the plane, and a certain "shape" (a connected, acyclic subgraph $S$ of $L$). The task is to approximately cover $L$ with translated, rotated and flipped ...
8
votes
2answers
200 views

Computed circuit complexity of decision problems

Has anyone explored what is the circuit complexity of classic decision problems such as Primes or Graph-Isomorphism for small input size $N$? While most people are interested in the how the scaling ...
12
votes
1answer
290 views

Gentle introduction to the algorithmic aspects of tree-depth

Treewidth and pathwidth are popular parameters, measuring the closeness of a graph to a tree or a path, respectively. Indeed, it seems treewidth is so popular it is featured in many papers, books, and ...
2
votes
3answers
135 views

Heuristic with worst-case exponential complexity

I have been working with some colleagues on a metaheuristic for an NP-Hard optimization problem. It is a genetic algorithm using a steady-state population replacement strategy (at each iteration a ...
5
votes
3answers
436 views

What is the application of combinatorial game theory

I find Combinatorial Game Theory very interesting as my primary interest is mathematics. My question is why do Computer Scientists (who tend to have a more practical approach) study it as well? Are ...
5
votes
1answer
257 views

Assignment problem with multiple workers for each job

I am wondering if there are any results on the following version of the assignment problem. We are given a set of jobs $J$ and a set of workers $W$, and for each job $j$ and worker $w$ we are given ...
6
votes
1answer
111 views

Lexicographic perturbation for euclidean shortest path instances?

Assume we have an undirected graph $G=(V,E)$ and vertex locations $\pi: V \rightarrow \mathbb{R}^2$. I am looking for a procedure to perturb the vertex positions to obtain new positions $\pi'$ such ...
20
votes
1answer
500 views

Number of distinct differences of $\omega(\sqrt{n})$ integers chosen from $[n]$

I encountered the following result during my research. $$\lim\limits_{n\to \infty} \mathbb{E}\left[ \frac{\#\{|a_i-a_j|,1\le i,j\le m \}}{n} \right] = 1$$ where $m=\omega(\sqrt n)$ and ...
18
votes
2answers
382 views

“Embedding” a language in itself

Main/General Question Let $L$ be a language. Define the languages $L_i$ with $L_0 = L$ and $$L_i = \{xwy : xy \in L_{i-1}, w \in L\}$$ for $i \geq 1$. Consider $\hat{L} = \bigcup L_i$. So, we ...
7
votes
1answer
198 views

Embedding a graph in the euclidean space

Given a graph $G=(V,E)$, find a mapping $f\colon V \rightarrow \mathbb R^d$ such that for every edge $(u,v) \in E$ we have that $||f(u)-f(v)|| \leq r$; and for every $(u,v) \not \in E$, we have the ...