Questions tagged [np-hardness]

Questions related to NP-hardness and NP-completeness.

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Are there any NP-complete for continuous mathematics? [closed]

Looking at this wiki page, it seems most NP-complete problems are based on discrete structures, such as graphs. What are some problems that involve real or complex analysis instead of discrete ...
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1answer
155 views

Is pooling-aware bin packing NP-Hard?

I am unable to prove whether the following problem is NP-Hard. It seems like a bin-packing or a partition problem, without being close enough to either of them (at least I do not see the reduction to ...
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31 views

Sparse coding and matching pursuit algorithms

Is it true that all known sparse coding algorithms which work efficiently in practice don't have convergence proofs and always use an intermediate step of a matching/subspace pursuit algorithm on the ...
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27 views

How does one know what is not in a certain class of pseudo-distributions?

We consider working in the function space $\mathbb{R}^{\{ -1,1\}^n}$ where the expectation inner-product makes the juntas form a $2^n$ dimensional orthonormal basis. Now say one has found a degree $...
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182 views

At what parameters is following $NP$-hard?

Problem Instances at given $\alpha>0$. $(1)$ Given $a_1,\dots,a_{n^\alpha}\in\Bbb Z$ with $|a_i|\in(2^{n-1},2^n-1)$ is there a subset of that sums to $0$? $(2)$ Given $a_1,\dots,a_{n}\in\Bbb Z$ ...
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53 views

About increasing the objective values of certificates for Max-Clique SDP

Say you write a round-k Lasserre (or any other hierarchy!) SDP relaxation of the Max-Clique problem. Lets say one now finds (or knows how to sample with high probability) a graph $G_1$ of size $n$ and ...
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172 views

Is “Binary Interval Tree” NP-hard? [closed]

The input is set of (disjoint) intervals $I$. The output should be the following rooted binary tree. Each leaf node corresponds to an interval from $I$. Each interior node contains an interval which ...
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143 views

Quantum computer versus Random 3-SAT?

It seems to be commonly believed that quantum computer cannot efficiently solve NP-hard problems. What about the challenging problems in average-case, such as Planted Clique and Random 3-SAT?
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496 views

Is this problem #P-hard and why?

Problem: In a directed graph $G=(V,E)$, each edge $e\in E$ is associated with a weight $w_e$ which is geometrically distributed with a parameter $p$, i.e. $P(w_e=i)=p(1-p)^{i-1}, i\geq 1$. $s,t$ are ...
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69 views

Multicuts (or multiway cuts) for 3 Terminals of Minimum Capacity

For each fixed $k \geq 3$, the following well-known problem is NP-complete. k-Multicut (aka "Multiway Cut", "k-Way Cut", "Multicut") Input: $(N,l)$ where $N=(V,E,T,c)$ is an undirected $k$-terminal ...
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272 views

Finding an equivalent NP-complete instance for this game-theory problem

I apologize if this question is not a good fit for CSTheory. I'm a PhD student who has just started out and I'm working on a game-theory problem in one of my classes. Although my professor hasn't ...
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920 views

Is there a reduction from a 0-1 knapsack problem to the unbounded problem?

As we know, an unbounded knapsack problem could be described as: $\max \sum_{i=1}^nc_1x_i$ s.t. $\sum_{i=1}^na_ix_i\le b$ $x_i\ge0,x_i\in\mathbb Z,i=1,\cdots,n$ And for an 0-1 knapsack problem, we ...
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45 views

Bounding the cost of an approximation algorithm when subtraction involve [closed]

Given an algorithm with approximation ratio $\alpha$, and another algorithm with approximation ratio $\beta=n^\epsilon$, and a solution to a problem with cost $c$. What is the standard way to bound $\...
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57 views

Help in NP-Hardness proof of a certain type of Class Cover problem

Class Cover Problem is nothing but finding an optimal cover of certain class (Point Set) with a particular shape only i.e. finding minimum number of a certain shaped polygon (for example, rectangle) ...
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278 views

Partially filled jigsaw puzzle with six types of tiles

This is a slight variation of the question Are 'zero-one' jigsaw puzzles NP-complete? asked on cs.stackexchange.com. What is the complexity of the following problem? Input: an $n\times n$ Jigsaw ...
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241 views

What are the consequences of a ${\bf O}$(m) algorithm for SAT

We are given a Boolean formula $F$ in conjunctive normal form with $n$ variables and $m$ clauses and we would like to know if there exists at least one assignment to the $n$ variables that makes $F$ ...
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302 views

NP-Completeness of Certain Bounded Degree Graphs [closed]

I was studying time complexity when it comes to bounded degree graph problems and I was wondering if I can get help with the following two problems. 1) Is the set of all (G, k) where G is a graph ...
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373 views

Hardness of min-max problems

Consider the following min-max problem Given a graph $G=(V,E)$ and an integer $k \geq 0$, delete at most $k$ nodes in $G$ to maximize the size of the minimum dominating set in the residual graph. ...
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1k views

A variation of the subset sum problem [closed]

The subset sum problem is NP Complete. I was wondering if the following variation can be proved to be NP Complete : The cardinality of set of integers is $m$. And each element of the set is between $...
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912 views

Where is the error in the following P != NP pseudo-proof ?

Here is a necessarily wrong proof of $P \neq NP$ as it relativizes, but I can't find the error : Le $U$ be a universal Turing machine, whose inputs are restricted to Turing machines accepting ...
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491 views

Formalized configuration of Subset sum problem Worst-case ? [closed]

Is there a formal proof of the worst-case configuration of the subset sum problem? In other words - is there a set proven to be the hardest to find a subset equals to 0 from? thanks
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505 views

Is DNF-Equivalence Problem $\mathsf{NP\mbox{-Hard}}$?

I have the following Equivalent DNF problem: Input:Two DNF formulas, $F_1$ and $F_2$,with variables $a_1,a_2,...a_n.$ Output: $1$ if $F_1$ and $F_2$ are equivalent, $0$ otherwise. $F_1$ and $F_2$ ...
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772 views

graph coloring with 3 colors

I'm searching for an algorithm that can calculate a suboptimal solution for: color a graph with 3 colors some vertices already have a color and can't be changed the edges have values and the ...
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145 views

Subset Sum Problem and hard looking instances that are not really hard

I have been working in a subset sum solver (some new approach) and while working on the time complexity analysis I found what I describe below. Maybe this could explain why some "hard looking" ...
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1answer
157 views

Find the shortest s-t trail(edge disjoint path) in a graph with negative weight edges

A walk in a graph is a finite or infinite sequence of edges which joins a sequence of vertices. A trail is a walk in which all edges are distinct. Note that a trial may visit a vertex multiple times ...
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214 views

NP-hard problems on the class of caterpillars

My question is whether there exist an NP-hard problem that has only a caterpillar as input. By saying only caterpillar as input, I wanted to emphasize that no function (eg: weights on vertices or ...
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2answers
165 views

Geometric max cover

Consider $n$ points and a distance function $d$ that satisfies the triangle inequality. We are also given a number $r$. Each point $p$ defines a set $B_p$ (or a ball) that covers all other points ...
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1answer
268 views

NP-complete problems with optimal approximation in poly-time

I'm looking for examples of hard optimization problems, for which we have an optimal approximation (not that this is not the same as $PTAS$, as we require a completely tight approximation, and not $1+\...
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407 views

Hardness of an extended maximum set packing problem

(Edited) The maximum set packing problem when the sets are all of equal size, say $k$, is known to be NP-hard for $k \ge 3$. The requirement in this problem is that the sets in the solution will be ...
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3answers
596 views

Comparing graphs

I am looking for a kick in the right direction. What i am trying to do is to compute "similarity" between two graphs, where I define "similarity" as the number of shared paths. example: ...
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1answer
76 views

Constrained Topological Sorting with bounded number of chains

In general, constrained topological sorting is NP-hard. Now we add another constraint to it, such that take any k+1 nodes and there will be at least one pair ...
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250 views

PTAS (polynomial time approximatin scheme) for euclidean TSP/Minimum-Cost k-Connected subgraph problem

Problem 1 I have read "On Approximation of the Minimum-Cost k-Connected Spanning Subgraph Problem" (by A. Czumaj, A. Lingas), and even in the abstract are 2 statements "We present a polynomial time ...
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Is the counting version of 1-in-3 Sat #P-complete?

In the paper "Hard Tiling Problems with Simple Tiles", Moore and Robson prove that Cubic Planar Positive 1-in-3 Sat in NP-complete by a reduction from Positive 1-in-3 Sat. Cubic Planar Positive 1-in-...
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69 views

About using smoothness of the Hessian for getting to approximate criticality of a non-convex objective

Is there any algorithm which shows that under the assumption of Lipschitz smoothness of the Hessian of a non-convex function one can get to its critical point faster?
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226 views

Is there any reference on the hardness of approximation for 2-partition problem?

I tried to look for some references but could not find any. I knew it is proved to be NP-complete via a transformation from Knapsack or 3DM problem. But I couldn't find a way to apply PCP theorem to ...
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75 views

NP-Hard Knapsack Instances

Consider the classic Knapsack optimization problem (KP): Given $p_1, \dots, p_n, w_1, \dots, w_n, B\in\mathbb N$, compute a solution $I\subseteq \{1,\dots,n\}$, such that $\sum_{i\in I} w_i \leq B$ ...
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45 views

Complexity of multi-objective optimization problems

How can we define and prove the worst-case complexity of multi-objective optimization problems (MOOP)? It is easy to see that, if one of the objectives is an NP-Hard optimization problem, then the ...
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101 views

Network Reliability Problem

Network reliability, in which we are given an undirected graph $G$ with a failure probability $p_e$ for each edge and we are asked to calculate the probability that the network becomes disconnected ...
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62 views

Generalization of k-Coloring: maximizing the number of vertices with no neighbours of same color

One can consider the following generalization of the $k$-Coloring problem: Let be given a graph $G$ and an two integers $k$ and $p$. A vertex $v$ of $G$ is properly colored if $v$ has no neighbour ...
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60 views

About complexity of recovering or learning Bayesian networks

Are there complexity theoretic results about recoverability or learnability of the marginals (of the source vertices) and the conditionals (along each of the edges) of a Bayesian network from having ...
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33 views

On approx-preserving P- and A-reducibilities

Let $X$ and $Y$ be two NPO problems. Let $(f,g)$ be a reduction between $X$ and $Y$, in particular, assume that $(f,g)$ is both P-reduction and A-reduction, i.e., there exist two poly-time ...
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154 views

NP-hardness of minimizing sum of complicated objective function

In our research, we faced the following problem optimization problem: Input: a list of $k$ pairs of positive integers $(n_1,d_1), \ldots, (n_k,d_k)$; an integer $m$. Output: $P$, a partition of the ...
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443 views

Hardness of Minimizing Submodular Functions with Cardinality Constraints

I am new to submodular functions and I am reading the introductions to submodular functions and applications ( https://www.ima.umn.edu/optimization/seminar/queyranne.pdf ). In this introduction, it ...
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70 views

Finding exact value with a quotients of products of random values

Sorry for the haphazard title: really not sure what this should be called Suppose we have a set of $z$ random values $S = r_1, \dots, r_z$ drawn from $\mathbb{Z}_N$ (where $N$ is some large prime). ...
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112 views

Minimum Weight Ordering of nodes on a directed graph

I'm bumping my head against the wall trying to prove this problem is NP-complete (it might not be) Let $G = (V,E)$ be a directed graph with weights $w:E \to \mathbb{R_{\geq 0}}$ on the edges. The ...
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761 views

Algorithm to maximize profit: ways to solve/approach? (Advanced NP-Complete)

This one's hard, so all help really appreciated! I know it is NP-Complete and thus cannot be solved in polynomial time, but looking for help in analysis, i.e. what type of NP-Complete problem it ...
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353 views

Maximize Covering Minimizing the Overlap

I have this problem: Given a collection of sets $S:\{S_{1},...,S_{k}\}$ where each set $S_{j}$ is a subset of $U:\{e_{1},...,e_{n}\}$ universe of elements. I would find-out a subset $C \subseteq S$ ...
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225 views

Does coNP-hardness imply NP-hardness [duplicate]

Possible Duplicate: Do many-one reductions and Turing reductions define the same class NPC Hi, Is the following true: If L is coNP-hard, then L is NP-hard. I have found statements of this, ...
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164 views

np completeness [duplicate]

Possible Duplicate: Reduction Algorithms Hi, I am thinking of researching in this area and am doing some analysis now. Need your help understanding the NP Completeness. I went through the ...
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774 views

What progress has been made to prove whether or not p=np? [closed]

I know that it is still one of the biggest mysteries of computer science whether non-deterministically polynomial problems can be solved in polynomial time. I am curious to know what makes this ...