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REPORTS > KEYWORD > RECONSTRUCTION:
Reports tagged with reconstruction:
TR10-067 | 14th April 2010
Sourav Chakraborty, Eldar Fischer, Arie Matsliah

Query Complexity Lower Bounds for Reconstruction of Codes

We investigate the problem of {\em local reconstruction}, as defined by Saks and Seshadhri (2008), in the context of error correcting codes.

The first problem we address is that of {\em message reconstruction}, where given oracle access to a corrupted encoding $w \in \zo^n$ of some message $x \in \zo^k$ ... more >>>

TR11-061 | 18th April 2011
Neeraj Kayal

Affine projections of polynomials

Revisions: 1

An $m$-variate polynomial $f$ is said to be an affine projection of some $n$-variate polynomial $g$ if there exists an $n \times m$ matrix $A$ and an $n$-dimensional vector $b$ such that $f(x) = g(A x + b)$. In other words, if $f$ can be obtained by replacing each variable ... more >>>

TR11-153 | 13th November 2011
Ankit Gupta, Neeraj Kayal, Satyanarayana V. Lokam

Reconstruction of Depth-4 Multilinear Circuits with Top fanin 2

We present a randomized algorithm for reconstructing multilinear depth-4 arithmetic circuits with fan-in 2 at the top + gate. The algorithm is given blackbox access to a multilinear polynomial f in F[x_1,..,x_n] computable by a multilinear Sum-Product-Sum-Product(SPSP) circuit of size s and outputs an equivalent multilinear SPSP circuit, runs ... more >>>

TR12-033 | 5th April 2012
Ankit Gupta, Neeraj Kayal, Youming Qiao

Random Arithmetic Formulas can be Reconstructed Efficiently

Informally stated, we present here a randomized algorithm that given blackbox access to the polynomial $f$ computed by an unknown/hidden arithmetic formula $\phi$ reconstructs, on the average, an equivalent or smaller formula $\hat{\phi}$ in time polynomial in the size of its output $\hat{\phi}$.

Specifically, we consider arithmetic formulas wherein the ... more >>>

TR15-150 | 13th September 2015
Gaurav Sinha

Reconstruction of $\Sigma\Pi\Sigma(2)$ Circuits over Reals

Revisions: 3

Reconstruction of arithmertic circuits has been heavily studied in the past few years and has connections to proving lower bounds and deterministic identity testing. In this paper we present a polynomial time randomized algorithm for reconstructing $\Sigma\Pi\Sigma(2)$ circuits over $\R$, i.e. depth$-3$ circuits with fan-in $2$ at the top addition ... more >>>

TR19-104 | 6th August 2019
Vishwas Bhargava, Shubhangi Saraf, Ilya Volkovich

Reconstruction of Depth-$4$ Multilinear Circuits

We present a deterministic algorithm for reconstructing multilinear $\Sigma\Pi\Sigma\Pi(k)$ circuits, i.e. multilinear depth-$4$ circuits with fan-in $k$ at the top $+$ gate. For any fixed $k$, given black-box access to a polynomial $f \in \mathbb{F}[x_{1},x_{2},\ldots ,x_{n}]$ computable by a multilinear $\Sigma\Pi\Sigma\Pi(k)$ circuit of size $s$, the algorithm runs in time ... more >>>

TR20-045 | 15th April 2020
Ankit Garg, Neeraj Kayal, Chandan Saha

Learning sums of powers of low-degree polynomials in the non-degenerate case

Revisions: 1

We develop algorithms for writing a polynomial as sums of powers of low degree polynomials. Consider an $n$-variate degree-$d$ polynomial $f$ which can be written as
$$f = c_1Q_1^{m} + \ldots + c_s Q_s^{m},$$
where each $c_i\in \mathbb{F}^{\times}$, $Q_i$ is a homogeneous polynomial of degree $t$, and $t m = ... more >>> TR20-125 | 17th August 2020 Gaurav Sinha Efficient reconstruction of depth three circuits with top fan-in two Revisions: 2 In this paper we develop efficient randomized algorithms to solve the black-box reconstruction problem for polynomials(over finite fields) computable by depth three arithmetic circuits with alternating addition/multiplication gates, such that top(output) gate is an addition gate with in-degree$2$. Such circuits naturally compute polynomials of the form$G\times(T_1 + T_2)$, ... more >>> TR21-155 | 13th November 2021 Vishwas Bhargava, Ankit Garg, Neeraj Kayal, Chandan Saha Learning generalized depth-three arithmetic circuits in the non-degenerate case Revisions: 1 Consider a homogeneous degree$d$polynomial$f = T_1 + \cdots + T_s$,$T_i = g_i(\ell_{i,1}, \ldots, \ell_{i, m})$where$g_i$'s are homogeneous$m$-variate degree$d$polynomials and$\ell_{i,j}$'s are linear polynomials in$n$variables. We design a (randomized) learning algorithm that given black-box access to$f$, computes black-boxes for ... more >>> TR22-125 | 9th September 2022 Shir Peleg, Amir Shpilka, Ben Lee Volk Tensor Reconstruction Beyond Constant Rank We give reconstruction algorithms for subclasses of depth-$3\$ arithmetic circuits. In particular, we obtain the first efficient algorithm for finding tensor rank, and an optimal tensor decomposition as a sum of rank-one tensors, when given black-box access to a tensor of super-constant rank. Specifically, we obtain the following results:

1. ... more >>>

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