P versus NP and other resource-bounded computation.

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Topological properties of classes

Is there any reasonable natural way to think of closure properties of complexity classes such as closure of $PP$ or $PH$ is $PSPACE$? $P/poly$ is in interior of class $PP$ and so on?
9
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1answer
120 views

Is a quadratic nondeterminism speed-up of deterministic computation plausible?

This is a follow up to nondeterministic speed-up of deterministic computation. Is it plausible that nondeterminism (or more generally alternation) would allow a general quadratic speed-up of ...
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88 views

Is cyclic group specified as part of input in discrete logarithm problem? [on hold]

Which of two is the correct definition of discrete logarithm problem? Problem $1$: Input: prime $p$, generator $g$ of $\Bbb Z_p$ and an integer $h$. Output: $x$ such that $g^x=h\bmod p$. Problem ...
5
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0answers
50 views

Finding of dimension of algebraic varieties

I have found that the problem of finding of dimension of algebraic varieties over $\mathbb{C}$ is $NP$-complete (https://pdfs.semanticscholar.org/a947/463a29ee512b89823176f6e8c9f9b2bb1a5e.pdf). Are ...
13
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3answers
316 views

Nondeterministic speed-up of deterministic computation

Can nondeterminism speed-up deterministic computation? If yes, how much? By speeding-up deterministic computation by nondeterminism I mean results of the form: $\mathsf{DTime}(f(n)) \subseteq ...
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53 views

How often can a linear speed sort succeed? [migrated]

Let's say you have sorting function. It is allowed to exit with failure (but if it does not it must return a correctly sorted sequence). It is also $\mathcal O (n)$. What kind of bounds can we place ...
6
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2answers
325 views

Is it known whether $BPP\cap NP\subseteq RP$?

The reverse inclusion is obvious, as is the fact that any self-reducible NP language in BPP is also in RP. Is this also known to hold for non-self-reducible NP languages?
7
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1answer
222 views

Parity P and AM

What is known about non-trivial inclusions of $\oplus\mathsf{P}$ in other classes? In particular, is it known whether $\oplus\mathsf{P}$ is contained in $\mathsf{AM}$? The same questions apply to the ...
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2answers
156 views

Parametrized complexity of the 2-Long Paths Problem

Consider the following problem: Let $G=(V,E)$ be a graph, $s,t\in V$ vertices and $k\in\mathbb N$ an integer parameter. The 2-Long Paths Problems asks whether there exist two disjoint paths from ...
9
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154 views

Monotone circuit complexity of matroids?

Call a monotone boolean function $f$ a matroid function if its minterms are bases of some matroid. I am interested in monotone circuit complexity of such functions, even when we "tie hands" of these ...
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1answer
182 views

Is finding an optimal solution to this Knapsack-like problem NP-hard?

Suppose our inputs are a set of objects with weights $w_1,...,w_n$. We have two separate sets of profits: $p_1,...,p_n$ and $v_1,...,v_n$. We wish to maximize $ \sum_{i=1}^{n} p_i(1-x_i)+\alpha_i ...
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Complexity of computing the parity of read-twice opposite CNF formula ($\oplus\text{Rtw-Opp-CNF}$)

In a read-twice opposite CNF formula each variable appears twice, once positive and once negative. I'm interested in the $\oplus\text{Rtw-Opp-CNF}$ problem, which consists in computing the parity of ...
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130 views

Derandomization of Polynomial Identity Testing

There are some theorems that state $P = BPP$ if some condition is satisfied. For example, a theorem of Impagliazzo and Wigderson states tha $P=BPP$ unless $DTIME(2^{O(n)})$ has sub-exponential ...
3
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3answers
101 views

Canonisation of boolean matrices under row and column permutations

Consider the equivalence relation $\sim$ on boolean matrices $A,B\in\{0,1\}^{m\times n}$ which is defined as follows: $A\sim B$ :iff there are permutation matrices $P\in\{0,1\}^{n\times n}, ...
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Example of polynomial speedup over previously known exponential time complexity

In the IARPA-BAA-15-13, the term "polynomial speedup over exponential time complexity" is defined as follows. My question: Is there any example of polynomial speedup over exponential time ...
4
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71 views

Graph partition with weighted vertices and edges

I am searching for an algorithm to apply to a specific graph partition problem that I am interested in. It feels like a topic that people from CS may have worked on but it is also different from ...
13
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1answer
669 views

Rabin's “degree of difficulty of computing a function, and a partial ordering of recursive sets”

I am looking for: Michael O. Rabin, "Degree of difficulty of computing a function, and a partial ordering of recursive sets", Hebrew University, Jerusalem, 1960 Summary: “We attempt to measure ...
5
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1answer
192 views

The Average-case Complexity of Simplex Algorithm

I was wondering if there are any results on the average case complexity of the simplex algorithm. Let $A \in \mathbb{R}^{m \times n}$ be the matrix in the linear constraint. I know that Smale did ...
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102 views

Arithmetic complexity of matrix powering with non-commutative entries

Assume $M\in\Bbb Z_{\geq0}[x_1,\dots,x_n]^{m\times m}$ be an $m\times m$ matrix in $n$ variables with $x_i$ being non-commutative. What is the complexity class and circuit and formula complexity of ...
9
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228 views

Checking whether two quadratic equations have a common zero

Given two quadratic equations (with integer coefficients): $x^T A_1 x+ b^T_1 x + c_1=0$ and $x^T A_2 x+ b^T_2 x + c_2=0$ The problem is to decide whether they have a common zero. Here $x$ is a ...
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1answer
157 views

Packing sets to maximize overlap

For a set of sets $A$, let $\cup A := \cup_{S \in A} S$. Consider the following problem: Input: a list of $m$ weights $w = (w_1, \ldots, w_m)$, a list of $n$ distinct subsets $T = (S_1, \ldots, ...
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0answers
110 views

About lower bounding the sample complexity of a distribution

Given a joint probability distribution over a finite number of random variables (each with a finite range space) of which only a certain subset is observable, is there a notion of "sample complexity" ...
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1answer
85 views

Finding a minimum tree which is isomorphic to a subtree of $T_1$ but not to a subtree of $T_2$

Consider the problem that receives two trees $T_1$, $T_2$, and asks to find a minimum size tree $T$ such that there exists a subtree of $T_1$ which is isomorphic to $T$, but there is no such ...
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3answers
449 views

Examples of successful derandomization from BPP to P

What are some major examples of successful derandomization or at least progress in showing concrete evidence towards $P=BPP$ goal (not the hardness randomness connection)? The only example that comes ...
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1answer
162 views

Zero of a multivariate cubic equation

Given a multivariate cubic equation $f(\vec{x})$ over reals where all coefficients of $f$ are integers, and a hyper-rectangle $B=\bigwedge_i x_i\in[a_i, b_i]$ where $a_i, b_i$ are constant integers, ...
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142 views

When will an NP-complete language remain hard if half of a witness is revealed with the instance?

Let $L$ be an NP-complete language. Let $W(x)$ denote the set of (polynomially length bounded) witnesses that certify $x\in L$. That is, $x\in L$ if and only if there exists a $w$, such that $w\in ...
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115 views

Complexity of counterexample function and bounded arithmetic

Let $\{L^c_i\}_{i}$ be an efficient enumeration of languages in $DTime(2^{n^c})$, e.g. clocked TMs. Assume $EXP\not = NEXP$. Let $L$ be an $NEXP$-complete language and therefore not in $EXP$. There ...
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102 views

Recognition of a primitive root

Adleman and McCurley published a paper in 1994 called "Open problems in number theoretic complexity, II" (http://ww.cstheory.com/papers/open.ps.gz) Problem 18 of this list of open problems is about ...
8
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1answer
165 views

Verifying a subtlety of Karp's original proof that SAT has a polynomial time reduction to 3SAT

Stated briefly, my question is: is Karp's original proof reducing SAT to 3SAT unnecessarily elaborate? The details are as follows. In his 1972 paper Reducibility Among Combinatorial Problems, Karp ...
6
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1answer
125 views

Does k-PATH admit a constant approximation?

In the $k$-PATH problem, we receive as input a graph $G$ and an integer $k$. The goal is to decide whether there exists a simple path of length $k$ in $G$. A $\alpha$-approximation for $k$-PATH is an ...
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1answer
385 views

Are arithmetic circuits weaker than boolean?

Let $A(f)$ denote the minimum size of a (non-monotone) arithmetic $(+,\times,-)$ circuit computing a given multilinear polynomial $$ f(x_1,\ldots,x_n)=\sum_{e\in E}c_e\prod_{i=1}^n x_i^{e_i}\,, $$ ...
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1answer
105 views

Existence of solution for a system of multi-variate polynomial equations and in-equations

Formally, I have 2 finite sets of polynomials : $P = \{p_1, p_2, p_3, ...p_m\}$ and $Q = \{q_1, q_2, q_3, ...q_n\}$, where for $1 \leq i \leq m$, and $1 \leq j \leq n$, I have $p_i, q_j \in ...
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1answer
86 views

In regards to the tautologies of a polynomially-bounded propositional proof system

In the book 'Logical Foundations of Proof Complexity', co-authored by Stephen Cook, the following definition is given: A proof-system $F$ is said to be polynomially-bounded if there is a polynomial ...
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107 views

Computing $a^e \mod p^n$ Efficiently

It is well known that we can compute: $$ a^e \mod m $$ in $O(\log e \log ^2 m)$ bit operations (assuming multiplication $nm$ in $O(\log n \log m)$ time) via exponentiation by squaring. I am wondering ...
8
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1answer
143 views

Complexity of the edge-disjoint cycle covers

I am interested in decompositions of a directed graph $G=(V,E)$ into non-intersecting Eulerian subgraphs $G_i=(V_i, E_i)$. I want to find the decomposition that covers the largest number of edges. I ...
6
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1answer
127 views

Does p-isomorphism preserve phase transition?

Consider two NP-complete languages that are polynomial-time isomorphic. If we know that one of them exhibits phase transition (with respect to some order parameter), does this imply that the other ...
6
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56 views

Can Quarter-Subset Membership be decided space-efficiently?

Consider the following decision problem. Let $q = \sum_{i=0}^{n/4} \binom{n}{i}$ and let $(C_0^n, C_1^n,\dots,C_{q-1}^n)$ be a suitable enumeration of those subsets of $\{0,1,\dots,n-1\}$ that have at ...
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172 views

Proving P-Isomorphism between two languges

The famous Isomorphism Conjecture states that all NP-complete problems are isomorphic via polynomial-time computable and invertible bijections (reductions). Padability is the only property that I know ...
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1answer
266 views

On Zero sum perfect matching

Fix $c\geq1$. Input is a $m$ vertex complete graph with edges assigned $a_1,\dots,a_{\frac{m(m-1)}2}\in\Bbb Z$ in some order. Is it $\mathsf{NP}$-complete to decide if there is a perfect matching of ...
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495 views

Deeper look at Algorithmica?

Russell Impagliazzo published "A Personal View of Average-Case Complexity" (preprint) back in 1995. He presented five possible worlds we could be living in, depending on how P and NP were related. The ...
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1answer
151 views

Huffman Tree Depth, Is there any theory?

I'd like to as a variation on this question regarding Huffman tree building. Is there any theory or rule of thumb to calculate the depth of a Huffman tree from the input (or frequency), without ...
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228 views

Maximizing the number of selected edges with opposing requirements

Consider the following problem: Input: a complete bipartite graph $G$ with its edges colored either white or black, a number $k$. Output: a subset of vertices $W$ of size $k$ which maximizes the ...
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#P-completeness and ModkP-completeness

If $\#A$ is the counting version of some corresponding decision problem $A$, when, if ever, can we determine solely on the basis of the complexity of the underlying decision problem that $\#A$ is ...
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1answer
142 views

Is length uniform AC0 computable?

Consider the following problem: Input: A binary string $w$. Output: $|w|$ as a binary number. Is it possible to compute this in $\mathsf{DLogTime}$-uniform $\mathsf{AC}^0$ (or equivalently in ...
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1answer
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On the difference between propositional proof system and polynomially-bounded proof system

For the definition of a propositional proof system we have: An abstract proof system is a polynomial time function f whose range is equal to the set of tautologies. If τ is a tautology, then an ...
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150 views

Oracle for NP complete problems

What if we had an oracle for solving all NP problems which has exactly one solution in polynomial time. The oracle fails if the NP problem has more than 1 solution. The question is can we use this ...
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1answer
214 views

Circuity complexity: monotone circuit of Majority function

As showed in the paper "Monotone Circuits for the Majority Function", is possible to construct a monotone boolean circuit for the majority function on n variables with size O(n^3) and depth 5.3 ...
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1answer
126 views

Graph class with easy chromatic number, but NP-hard coloring

Is there a graph class for which the chromatic number can be computed in polynomial time, but finding an actual $k$-coloring with $k=\chi(G)$ is NP-hard? Without any further restriction the answer ...
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108 views

NP Intermediate problems over Reals

While studying ${\bf NP}$ complete problems we have from Ladners' theorem - if ${\bf P}$ $\neq$ ${\bf NP}$-there are ${\bf NP}$ problems not in the class ${\bf P}$ nor ${\bf NP}$-complete. Ladners' ...
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A special case of the boolean multivariate quadratic polynomial problem

It's well known that in the general case, the boolean MQ problem: given $(f_1, \ldots, f_n) \in \mathbb{F}_2[x_1, \ldots, x_m]$ with $\deg(f_i) = 2$, can we find a solution $\vec{y}: f_i(\vec{y}) = ...