In this paper, we give the first subexponential (in fact, quasi-polynomial time) reconstruction algorithm for depth-3 circuits of any constant top fan-in ($\Sigma\Pi\Sigma(k)$ circuits) over $\mathbb R$, $\mathbb C$, or any large characteristic finite field $\mathbb F$. More explicitly, we show that for any constant $k$, given black-box access to ... more >>>
While efficient randomized algorithms for factorization of polynomials given by algebraic circuits have been known for decades, obtaining an even slightly non-trivial deterministic algorithm for this problem has remained an open question of great interest. This is true even when the input algebraic circuit has additional structure, for instance, when ... more >>>