Questions tagged [algebraic-complexity]

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2 votes
1 answer
134 views

Polynomial Identity Testing for $\prod \sum \prod$

I am reading a survey on polynomial identity testing by Saxena. On page 6 he writes that PIT for depth-3 circuits of the form $\prod \sum \prod$ is trivial. He gives no citation and as such I believe ...
4 votes
0 answers
48 views

Complexity of solving random underdetermined polynomial equations over finite fields

Consider a random system of degree-$d$ polynomials, with $n$ variables and $m$ equations, over some finite field $\mathbb{F}_q:$ $$\begin{align}\sum_{\substack{(\alpha_1,\dots,\alpha_n) \in \mathbb{Z}...
7 votes
1 answer
387 views

Can reciprocal inputs speed up monotone computations?

A $(+,\times,1/x_i)$ circuit is a standard monotone arithmetic $(+,\times)$ circuit with the only difference that now besides the input variables $x_1,\ldots,x_n$, also their reciprocals $1/x_1,\...
14 votes
1 answer
828 views

VC dimension of polynomials over tropical semirings?

As in this question, I am interested the $\mathbf{BPP}$ vs. $\mathbf{P}$/$\mathrm{poly}$ problem for tropical $(\max,+)$ and $(\min,+)$ circuits. This question reduces to showing upper bounds for the ...
5 votes
1 answer
157 views

Arithmetic Circuit Hierarchy?

The answers to the following question - Hierarchy theorem for circuit size give a "circuit hierarchy theorem" for boolean circuits. Does there exist a similar hierarchy theorem for ...
3 votes
0 answers
214 views

Is the Fueter-Polya Conjecture proven

The Fueter–Pólya conjecture states that if $\pi$ is a polynomial function and a bijection from $\mathbb{N}^2$ to $\mathbb{N}$ then $\pi$ must be the Cantor pairing function ($(x,y) \mapsto 1/2(x + y)(...
14 votes
2 answers
1k views

Gaussian Elimination in terms of Group Action

Gaussian elimination makes determinant of a matrix polynomial-time computable. The reduction of complexity in computing the determinant, which is otherwise sum of exponential terms, is due to ...
0 votes
0 answers
71 views

Can every reducible multivariate polynomial be partitioned into product of univariate polynomials of algebraically independent elements?

Lets say we define a reducible multivariate $f \in \mathbb{F}[x_1,...,x_n]$ to be partionable by $y_1,...,y_r \in \mathbb{F}[x_1,...,x_n]$ iff \begin{equation} f(x_1,,,,.x_n) = f_1(y_1)\cdot f_2(y_2) \...
37 votes
5 answers
2k views

Integer multiplication when one integer is fixed

$n$ is a parameter in the problem. For every $n$ we pick a random integer $a_n\in\{2^{n-1},2^{n-1}+1,\dots,2^n-1\}$ where $n\in\{1,2,\dots\}$. Problem: Given $n$ what is the complexity of ...
3 votes
0 answers
99 views

Complexity of checking if a given prime number can be computed using at most $s$ addition/multiplication operations?

Given are a prime number $p$ and a parameter $s\in\mathbb{N}$. What is the computational complexity of the problem of determining whether $p$ is computable by a series of at most $s$ steps, each being ...
5 votes
1 answer
128 views

DET is $VQP-complete$ and also $DET\in VP$ Does that mean $VP=VQP$

We know that $DET$ is in $VP$. And also from https://conferences.mpi-inf.mpg.de/adfocs-17/material/MB_LN.pdf I came to know that $DET$ is $VQP-complete$. Now certainly $VP\subseteq VQP$. That implies $...
0 votes
1 answer
79 views

In depth reduction of arithmetic formula why we get a $v$ st $\frac{s}3\leq |\Phi_v|\leq \frac{2s}{3}$

I am reading Depth Reduction of Arithmetic Formula form the survey of Ramprasad Saptharishi. Now in the proof of depth reduction due to Brent, 74 that Let $f$ be an n-variate degree d polynomial ...
4 votes
0 answers
77 views

How to learn the intuition behind probabilistic arguments in Algebraic Complexity lower bounds

I was reading the lower bounds of arithmetic circuits. There in the proof of the theorem Over field $\mathbb{F}_q$, determinant, permanent requires depth-3 circuits of size $2^{\Omega(n)} $ [...
0 votes
0 answers
65 views

Any arithmetic circuit of size $s$ and depth $\Delta$ can be converted to a formula of size $s' \leq s^{\Delta}$

I was reading Ramprasad Saptharishi's survey on Arithmetic Circuits. There in section 2.1.1 fact 2.3 it has Any arithmetic circuit of of depth $\Delta$ and size $s$, can be simulated by an arithmetic ...
0 votes
0 answers
64 views

Polynomial GCD exact complexity in terms of degree and number of variables

https://en.wikipedia.org/wiki/Polynomial_greatest_common_divisor#Proof_that_GCD_exists_for_multivariate_polynomials states multivariate polynomial GCDs may be defined over $\mathbb F_p[x_1,x_2,\dots,...
0 votes
1 answer
41 views

Decomposing outer product or general rank factorization over $\Bbb F_q$

Given matrix $M\in\Bbb F_q^{n\times n}$ with the promise that there are two matrices $A\in\Bbb F_q^{n\times 1}$ and $B\in\Bbb F_q^{1\times n}$ such that $AB=M$ is there a deterministic $O((n\log q)^c)$...
3 votes
1 answer
913 views

Complexity of matrix diagonalization

I'm probably missing a trivial answer, but somehow I can't find it. Given symmetric matrix $A \in \mathbb R^{n \times n}$, what's the complexity of diagonalizing the matrix, i.e. finding diagonal $\...
3 votes
0 answers
144 views

Nested dissection for singular matrices

Let $F$ be a field. Define $S_G(F)$ be the set of matrices $A$ in $F^{n\times n}$, such that if we replace all non-zero elements in $A$ with $1$, then we obtain the adjacency matrix of $G$ (the ...
8 votes
0 answers
201 views

"Addition function" that works for both perm and det simultaneously?

For $f = (f_n)$ a family of polynomials where $f_n$ is a polynomial in $n^2$ variables (which we can think of as the entries of an $n \times n$ matrix), say a function $S(A,B)$ is an addition function ...
7 votes
1 answer
932 views

Factoring with LLL when the form of the factors is given

Given a degree $2k$ reducible polynomial $$f(x)=\sum_{i=0}^{2k}a_ix^i\in\Bbb Z[x]$$ with $$\text{gcd}(a_{2k},\dots,a_0)=1$$ that is known to be of the form $f_1(x)f_2(x)$ with $\text{deg}\big(...
6 votes
1 answer
270 views

VNP is closed under taking coefficients using Valiant's criterion

We consider the family of polynomials $$\{f_n(x_1,\dots,x_n,y_1,\dots,y_n)\}\in\mathsf{VNP}$$ We want to show that the family $$\{h_n(x_1,\dots,x_n)\}$$ is in $\mathsf{VNP}$. Where $h_n(x_1,\dots,...
5 votes
1 answer
394 views

Questions about P vs NP and geometric complexity theory

Reading through various papers on geometric complexity theory (GCT), there is one thing, which pops up, while claimed in various places, that it is an approach to P vs NP, all the results seems to ...
4 votes
1 answer
224 views

Is $GCT$ necessarily a negative result program?

$GCT$ is a candidate program to separate permanent and determinant through symmetries. If indeed permanent and determinant can be handled in similar complexity class would $GCT$ be a program which can ...
1 vote
0 answers
1k views

How can I understand the Coppersmith–Winograd algorithm?

I want to do research on matrix multiplication algorithms. I glanced at the Coppersmith-Winograd algorithm paper, but I didn't understand anything. How can I complete the background to read this paper?...
2 votes
0 answers
140 views

Matrix multiplication when one matrix is fixed

Let $A$ be a fixed positive entried integer matrix of size $a\times n$ with $\ell$ bits per entry One is allowed to pre-process this matrix as appropriate. Given another positive integer entried $B$...
9 votes
0 answers
169 views

What are some examples of algorithmic applications of noncommutative rational identity testing?

The problem of polynomial identity testing (PIT) is known to be in $\mathsf{RP}$, but not known to be in $\mathsf{P}$. The related problem of noncommutative rational identity testing (NCIT) is known ...
1 vote
0 answers
103 views

Complexity of planted root of a system of quadratic homogeneous polynomials?

Given homogeneous degree $2$ randomly chosen polynomials $f_1,\dots,f_{m}$ in $\mathbb Z[x_1,\dots,x_n,y_1,\dots,y_n]$ each with only monomials $x_iy_j$ with condition that the system $f_1=\dots=f_{m}=...
1 vote
0 answers
26 views

Worst case polynomial in elimination theory under rank conditions?

Given $n$ polynomials $h_1(x_1,\dots,x_{2n}),\dots,h_{2n}(x_1,\dots,x_{2n})\in\mathbb Z[x_1,\dots,x_{2n}]$ where each of $h_1(x_1,\dots,x_{2n}),\dots,h_{2n}(x_1,\dots,x_{2n})$ is homogeneous of degree ...
20 votes
0 answers
637 views

Identifying Reducible/Irreducible polynomials over $Z[x]$

It is well known LLL algorithm provides a fully polynomial algorithm to factor a reducible primitive polynomial over $\mathbb{Z}[x]$. Say one only seeks to identify whether a given polynomial over $\...
5 votes
1 answer
203 views

Complexity of counting integer roots of multivariate polynomials in a polyhedron?

Deciding integer roots of multivariate polyomials is undecidable. However what is known about counting integer roots of multivariate polynomials in $\mathbb Z[x_1,\dots,x_m]$ with both $m$ and total ...
7 votes
0 answers
61 views

Complexity of deciding whether subspaces of Z_2^n cover every point 3*x times

When studying the complexity of checking identities in certain finite algebras, I came across the following decision problem: Input: A positive integer $n \in N$ and a set of affine subspaces $H_1,...
1 vote
0 answers
100 views

What is the relation between computational complexity of algebraic number and computational complexity to find the solution to algebraic equation?

Suppose $\alpha$ is algebraic number, and we have the algorithm with lowest computational complexity to output it, and $f(x)=0$ is algebraic polynomial with $\alpha$ as a root. If an algorithm which ...
1 vote
0 answers
71 views

Relating classes of computational complexity to finding solution to classes of algebraic equations [closed]

Having related classes of computational complexity to finding solution to classes of algebraic equations, we may relate classes of computational complexity to algebraic geometry or complex geometry,...
2 votes
2 answers
128 views

IPS upper bound for subset sum axiom

I am reading the following paper Michael A. Forbes, Amir Shpilka, Iddo Tzameret, Avi Wigderson ,"Proof Complexity Lower Bounds from Algebraic Circuit Complexity", 2016. IPS is defined as follows: ...
2 votes
0 answers
134 views

On $\Sigma \Pi \Sigma \Pi(2,r)$-circuits

As I understand from the survey "Progress on Polynomial Identity Testing - II" a polynomial-time algorithm for solving PIT for $\Sigma \Pi \Sigma \Pi (2, r)$ is unknown. However, there exists paper ...
1 vote
1 answer
188 views

What is the computational complexity of solutions over $\mathbb{Q}$ of polynomial equation with coeffiecents over $\mathbb{Z}$

What is the complexity of the following problem? (e.g. best-known running time, space, best upper bound in terms of complexity classes, etc.) Input: A multivariate polynomial $f$ with coefficients ...
9 votes
0 answers
304 views

What does a private coin $\mathsf{IP}$ protocol for Hilbert's Nullstellensatz look like?

$\mathsf{GNI}$ Private Coin In [GMW85], the authors provided the famous interactive proof $\mathsf{IP}$ of Graph Non Isomorphism $\mathsf{GNI}$. The $\mathsf{GNI}$ protocol entails a verifier ...
3 votes
0 answers
47 views

Equal degree factoring of homogeneous polynomials over $\Bbb Q[x_1,\dots,x_n]$?

Given $f(x_1,\dots,x_n)\in\Bbb Q[x_1,\dots,x_n]$ of form $\prod_{i=1}^df_i(x_1,\dots,x_n)$ where each of $f,f_i$ are homogeneous and each $f_i$ is irreducible what is the best technique to factor such ...
7 votes
1 answer
638 views

Riemann Hypothesis and Complexity Theory

It is known that "Assuming the generalized Riemann hypothesis (GRH) if VP = VNP then PH collapses to second level". Why would one think of a relation between VP,VNP and the Riemann hypothesis. Where ...
7 votes
1 answer
241 views

Sorting using ring operations

Sorting is in $\mathsf{NP}$. Given a sorted list, it is trivial to check sortedness in linear time. Is there any evidence sorting of elements from an ordered gcd domain(eg: $\Bbb Z$) cannot be done ...
1 vote
0 answers
29 views

A question about a claim in "No occurrence obstructions in geometric complexity theory"

It the new preprint Peter Bürgisser, Christian Ikenmeyer, Greta Panova, "No occurrence obstructions in geometric complexity theory", 2016 it is stated that 1.3. Conjecture (Mulmuley and Sohoni ...
9 votes
0 answers
268 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 ...
7 votes
0 answers
169 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 ...
5 votes
1 answer
201 views

Implications of a recent negative result to geometric complexity

A paper was posted in arxiv http://arxiv.org/pdf/1512.03798.pdf titled 'Rectangular Kronecker coefficients and plethysms in geometric complexity theory' by Christian Ikenmeyer and Greta Panova with ...
25 votes
2 answers
2k views

Sum-of-squares proof system

Recently I have seen several articles on arxiv that refer to a proof system called sum-of-squares. Can someone explain what is a sum-of-squares proof and why such proofs are important/interesting? ...
7 votes
1 answer
322 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 ...
8 votes
1 answer
520 views

Conditional results implying difficulty of improving upper/lower bounds for permanent

Let $A$ be a given square matrix. Is there any evidence that beating quadratic lower bounds for $B$ such that $\text{det}(B) = \text{per}(A)$ could be hard? Is there any plausible conjecture which ...
5 votes
0 answers
254 views

What is the status of Determinantal Complexity of Permanent

Recently Landsberg and Ressayre announced an exponential lower bound for permanent's determinantal complexity assuming certain symmetry conditions. What is the status of the problem of Permanent's ...
2 votes
0 answers
129 views

Complexity of a particular determinant

Suppose we have an $n\times n$ matrix $A$ with non-negative integer entries such that $\mathsf{Tr}(A^i)=0$ at every $i\in\{1,2,\dots,n-2,n-1\}$ and $\mathsf{Tr}(A^n)\neq0$, then from Trace-Determinant ...
18 votes
2 answers
2k views

Is there a theory that combines category theory/abstract algebra and computational complexity?

Category theory and abstract algebra deal with the way functions can be combined with other functions. Complexity theory deals with how hard a function is to compute. It's weird to me that I haven't ...