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Motivated by the Hadamard product of matrices we define the Hadamard
product of multivariate polynomials and study its arithmetic circuit
and branching program complexity. We also give applications and
connections to polynomial identity testing. Our main results are
the following.
\begin{itemize}
\item[$\bullet$] We show that noncommutative polynomial identity testing for
algebraic branching programs over rationals is complete for
the logspace counting class $\ceql$, and over fields of characteristic
$p$ the problem is in $\ModpL/\Poly$.
\item[$\bullet$] We show an exponential lower bound for expressing the
Raz-Yehudayoff polynomial as the Hadamard product of two monotone
multilinear polynomials. In contrast the Permanent can be expressed
as the Hadamard product of two monotone multilinear formulas of
quadratic size.
\end{itemize}
@InProceedings{arvind_et_al:LIPIcs.FSTTCS.2009.2304,
author = {Arvind, Vikraman and Joglekar, Pushkar S. and Srinivasan, Srikanth},
title = {{Arithmetic Circuits and the Hadamard Product of Polynomials}},
booktitle = {IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science},
pages = {25--36},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-939897-13-2},
ISSN = {1868-8969},
year = {2009},
volume = {4},
editor = {Kannan, Ravi and Narayan Kumar, K.},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2009.2304},
URN = {urn:nbn:de:0030-drops-23046},
doi = {10.4230/LIPIcs.FSTTCS.2009.2304},
annote = {Keywords: Hadamard product, identity testing, lower bounds, algebraic branching programs}
}