P versus NP and other resource-bounded computation.

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Finding an exactly weighted st-path in a digraph

I have a weighted digraph graph $G = (V,E)$ where the weights are positive and negative integers. The graph $G$ is not necessarily acyclic. The question is: given 2 nodes $v_1$ and $v_2$, is there a ...
8
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1answer
122 views

Is P equal to the intersection of all superpolynomial time classes?

Let us call a function $f(n)$ superpolynomial if $\lim_{n\rightarrow\infty} n^c/f(n)=0$ holds for every $c>0$. It is clear that for any language $L\in {\mathsf P}$ it holds that $L\in {\mathsf ...
0
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65 views

Complexity Book with Slides

Is there a good book on complexity theory (upper level undergraduate and/or graduate) that comes with slides prepared either by the author or by someone else (but that are specifically tailored to ...
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1answer
36 views

Is scheduling a set of tasks on single machine in P or in NP?

Given a set of tasks $T=\{t_1,\dots,t_n\}$ and execution times between the tasks $e(t_i,t_j)$ can we find a schedule $s$ for $T$ on a single machine with makespan $m_s < d$? Assume that the ...
4
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0answers
173 views

$NP \not\subseteq BPP \implies NP_{\mathbb{C}} \not\subseteq P_{\mathbb{C}}$

Stephen Smale claims in Mathematical Problems for the Next Century that $$NP \not\subseteq BPP \implies NP_{\mathbb{C}} \not\subseteq P_{\mathbb{C}}.$$ Can someone sketch the argument or provide a ...
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58 views

Subset sum problem solver (theoretical) time analysis

I has been thinking to a new approach to this problem and I'm wondering if next time analysis is right: Giving: $N$ = Number of Items $M$ = bits required to represent the maximum value in the set ...
2
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2answers
115 views

Complexity of smooth non-linear functions

EDIT: A more straightforward way of asking this question is: does evaluating a non-linear function require performing at least one multiplication? ORIGINAL QUESTION: I have an infinitely ...
11
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0answers
122 views

Lower bounds for the size of nondeterministic circuits

It is known that the minimum size of $U_2$-circuits computing the parity function exactly equals $3(n-1)$. The lower bound proof is based on the gate elimination method. Recently, I noticed that the ...
12
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2answers
180 views

Natural complete problems in higher levels of the $\mathsf{W}$-hierarchy

The $\mathsf{W}$-hierarchy is a hierarchy of complexity classes $\mathsf{W}[t]$ in parameterized complexity, see the Complexity Zoo for definitions. An alternative definition defines $\mathsf{W}[t]$ ...
8
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1answer
156 views

A purely graph-theoretic explanation of the reduction from Unique Label Cover to Max-Cut

I am studying the Unique Games Conjecture and the famous reduction to Max-Cut of Khot et al. From their paper and elsewhere on the internet, most authors use (what to me is) an implicit equivalence ...
7
votes
1answer
331 views

Problem that is in P only if P!=NP

Are there any problems that are solvable in polynomial time only if P!=NP, and otherwise solvable in (say) $O(2^n)$ time? A simple example would be: If P!=NP, compute a primality test for a random ...
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451 views

Consequences of $\oplus \mathbf{P} \subseteq \mathbf{NP}$

I have part of a proof attempt of $\oplus \mathbf{P} \subseteq \mathbf{NP}$. The proof attempt consists of a Karp reduction from the $\oplus \mathbf{P}$-complete problem $\oplus$3-REGULAR VERTEX COVER ...
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0answers
44 views

Homomorphism erasing information [closed]

I would be grateful if anyone could help me with the tricky exerciese *7.52 from Sipser's Introduction to the Theory of Computation 3rd ed. I got stuck in proving that, if P is closed under ...
4
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0answers
208 views

Is there a reason we haven't been able to prove that the existence of natural NPI problems even conditionally under assumption NPI is not empty?

We can write ${\mathsf {NP}}-{\mathsf P}= {\mathsf {NPC}}\cup {\mathsf {NPI}}$ where ${\mathsf {NPC}}$ is the set of ${\mathsf {NP}}$-complete languages (not in ${\mathsf {P}}$ by this partition), ...
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0answers
26 views

Understanding the time-complexity of Insertion Sort [closed]

From my textbook, I am studying the time-complexity of the insertion sort algorithm (shown below). The image above shows the times that each statement is executed. But wait, why is ...
22
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2answers
458 views

Is this variation of TQBF still PSPACE-complete?

Deciding if a quantified boolean formula such as $\forall x_1 \exists x_2 \forall x_3\cdots \exists x_n \varphi(x_1, x_2,\ldots , x_n),$ always evaluates to true is a classical PSPACE-complete ...
6
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1answer
191 views
1
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1answer
211 views

#P-complete problems are at least as hard as NP-complete problems

I just read J. Scott Provan, Michael O. Ball: The Complexity of Counting Cuts and of Computing the Probability that a Graph is Connected. SIAM J. Comput. 12(4): 777-788 (1983) and one of the first ...
12
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1answer
199 views

Large classes which contain LOGSPACE for which strict inclusions are unknown

The wikipedia page on PSPACE mentions that the inclusion $NL\subset PH$ is not known to be strict (unfortunately without references). Q1: What about $L\subset PH$ and $L\subset P^{\#P}$ - are these ...
8
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1answer
233 views

The exponential function over algebraic numbers

Given an algebraic number $\alpha$, I am interested in finding an approximation of $\Re(e^\alpha)$ up to a given precision, where $\Re()$ refers to the real part of the complex number. Formally, I ...
5
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0answers
100 views

Extensions of Affine Dispersers

A function $f\colon\{0,1\}^n\to\{0,1\}$ is called an affine disperser for dimension $d$, if for every affine subspace $S\subseteq \{0,1\}^n$ of dimension at least $d$, $f$ is not constant on $S$. This ...
4
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1answer
110 views

Inapproximability of $(\alpha, \beta)$ bi-criteria approximation

An $(\alpha, \beta)$ bi-criteria approximation algorithm for $k$-center is defined as an algorithm that returns a solution whose value is $\beta \cdot OPT$ ($OPT$ being the optimal solution for the ...
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1answer
80 views

Is this NP-Hard or does a known optimal polynomial time solution exist? [closed]

Suppose we have 10 items, each of a different cost Items: {1,2,3,4,5,6,7,8,9,10} Cost: {2,5,1,1,5,1,1,3,4,10} and 3 customers {A,B,C}. Each customer has a requirement for a ...
2
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1answer
151 views

Time complexity of d-dimensional convex hull

Consider the convex hull problem in $\Re^d$: Input: a list of $n$ points $S$ in $\Re^d$, Output: the vertices of the convex hull of $S$. What is the best lower bound on the time complexity of ...
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119 views

proving speedup phenomenon does not apply to any open complexity class separations

Aaronson recently wrote a blog refuting the idea that there could be some "glitch" in the formulation of the P vs NP conjecture[1] which reminds me of this following question. the Blum speedup ...
3
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0answers
118 views

How powerful are weak complexity classes with powerful oracles?

I am interested in complexity classes of the form $A^{B}$, where $A$ and $B$ are complexity classes such that $A \subsetneq \mathsf{P}$ and $\mathsf{NP} \subsetneq B$ are (believed to be) true. ...
4
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3answers
670 views

Factoring as a decision problem

I've seen in multiple places stating that factoring is in BQP and referencing Shor's algorithm, but Shor's algorithm is not solving a decision problem. How can factoring be restated in a decision ...
10
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1answer
246 views

Can affine lambda calculus solve every problem in P?

In Advanced Topics in Types and Programming Languages it is mentioned, in the chapter on sub-structural type systems, that a "carefully crafted" affine lambda calculus with a recursion combinator for ...
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126 views

Is RAMSEY COLORING in $NC$?

Say that a function $f$ is a RAMSEY COLORING if on unary input $n$, it returns a complete graph on $n$ vertices with its edges colored red and blue without a monochromatic clique of size $10\log n$. ...
7
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1answer
156 views

what is known about efficient set intersections

Say you have a number of sets of integers ($S_1, S_2 ... S_n$), and you want to calculate intersections of some of them ($\cap S_1, S_3, S_7$ might be a query, but you want to support many such ...
4
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1answer
367 views

Example of #P-intermediate problem

The previous question Do there exist intermediate problems (in the sense of Ladner's Theorem) for FP vs. #P? I assume that something is known, because I read some papers concerned with FP/#P ...
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186 views

NP-hardness of tasks graph assignment to two heterogenous servers

I have a problem with determinig if the following assignment problem is NP-hard. Any comments and suggestions would be appreciated. Problem definition Given is a directed acyclic graph $G=(V,E)$ ...
9
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2answers
499 views

Complexity of solving linear equations

What is known about the complexity of solving a system of linear equations over some finite field? I know that there exists an $O(n^3)$ algorithm (Gauss) that computes a solution and that for sparse ...
0
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1answer
129 views

Does $\# \mathsf{P}\subseteq \mathsf{FP}^{\mathsf{PH}}$?

The Toda's theorem is a relationship between two different complexity classes: $ \# \mathsf{P} $ and $PH$. He proved that $ \mathsf{PH}\subseteq \mathsf{P}^{\#\mathsf{P}} $. I wonder the following ...
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2answers
118 views

Primitive Recursive Definition : Binary numbers

Usually primitive recursive functions are define from Zero, Identity and Successor, projectors, composition and recursion. But you obtain algorithms that works with unary numbers. For example, the ...
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69 views

Padding Arguments for Probabilistic Classes

Do padding arguments exist for probabilistic classes? For example, would $P=BPP\Rightarrow EXP=BPEXP$? What about for space bounded computation? Would constant space derandomization imply $L=RL$ or ...
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0answers
49 views

Known time complexity advantage of quantum algorithms over classical algorithms [duplicate]

I know that this question may depend on how one formulates each complexity class, but in general, what time complexity advantage does quantum algorithms have over classical algorithms?
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121 views

Definition of Planar 3-SAT

What is the standard definition of Planar 3-SAT? I have seen a number of different definitions. What was the original paper that defined it and proved it to be NP-complete?
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NEXPTIME-completeness with more time for reductions

One thing that surprised me when learning about complexity theory is that for a complexity class C, we tend to define C-complete using polynomial time reductions, even when C is a very large ...
4
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1answer
252 views

Hardness of UNAMBIGUOUS-3DM

Let UNAMBIGUOUS-3DM be defined by analogy to UNAMBIGUOUS-SAT, i.e. as a promise problem version of three-dimensional matching where we may assume there is no more than one solution. Is there a ...
13
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How can one find the “hard” probability distribution on the input for recursive boolean functions?

Update: Since, it seems there is no progress regarding this question, any idea, conjecture, hunch, or advice is welcome. For example, are there any partial or incomplete results? What are the main ...
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Is graph coloring complete for poly-APX?

Is the graph coloring problem complete for poly-APX under C-reductions (alternatively, under AP-reductions)? For the graph coloring problem, speaking of a feasible solution means a proper coloring for ...
3
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1answer
133 views

Lower bounds for Polynomials computing the boolean functions

Expressing a boolean function $f$ $:\{ 0,1 \}^{n} \rightarrow \{0,1 \}$ using a polynomial $P(x_{1},...,x_{n})$, where $x_{1},...,x_{n}$ may be integer, finite fields, or other fields. One of the ...
4
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1answer
268 views

Reduction from SAT to 0,1 integer linear program with zero or one solutions

Probably this is well known. There is probabilistic reduction from SAT to Unique SAT (0 or 1 solutions). According to answer and comments derandomizing the reduction would imply $PH \subseteq \oplus ...
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309 views

$RL=L$ Progress Since 2006

Reingold, Trevisan, and Vadhan's breakthrough 2006 paper (http://dl.acm.org/citation.cfm?id=1132583) reduced the problem of showing $RL=L$ to producing pseudorandom walks on regular digraphs that are ...
10
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1answer
405 views

NP-complete problem with polynomially many certificates?

Let's call a language $L \in$ NP sparsely certificated if and only if: There exists a polynomial $p : \mathbb{N} \rightarrow \mathbb{N}$ such that for every input $x \in \Sigma^*$ of size $n$, if $x ...
3
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2answers
273 views

How hard is a variant of graph automorphism problem?

I'm interested in a variant of graph automorphism problem (which is $NPI$ candidate). Restricted GA Input: Given an undirected graph $G(E, V)$, and $\epsilon |V|/2$ pairs of nodes $(u, v)$ where $u ...
5
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3answers
294 views

Problems in $\text{PSPACE} \cap \text{Co-NP-Hard}$

I'm in search for examples of decision problems lying in $\text{PSPACE}\cap \text{coNP-hard}$ which are also not (known to be) in $\text{coNP}\cup \text{NP}\cup \text{NP-hard}\cup ...
5
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2answers
125 views

Is there an oracle separating Parity-P from PSPACE?

Is $ (\oplus \mathsf{P})^A \not \supseteq \mathsf {PSPACE}^A$ for some language $A$?
12
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1answer
595 views

A course for learning algebraic complexity

I want to learn about algebraic algorithms and complexity thoery. In particular, I am interested in PIT. Is there a set of lecture notes, books, papers and surveys for students who have read standard ...