Nearly optimal edge estimation with independent set queries

Abstract: We study the problem of estimating the number of edges of an unknown, undirected graph $G=([n],E)$ with access to an independent set oracle. When queried about a subset $S\subseteq [n]$ of vertices the independent set oracle answers whether $S$ is an independent set in $G$ or not. Our first main result is an algorithm that computes a $(1+\epsilon)$-approximation of the number of edges $m$ of the graph using $$\min(\sqrt{m},n / \sqrt{m})\cdot\textrm{poly}(\log n,1/\epsilon)$$ independent set queries. This improves the upper bound of $$\min(\sqrt{m},n^{2/m)\cdot\textrm{poly}(\log} n,1/\epsilon)$$ by Beame et al. \cite{BHRRS18}. Our second main result shows that ${\min(\sqrt{m},n/\sqrt{m}))/\textrm{polylog}(n)}$ independent set queries are necessary, thus establishing that our algorithm is optimal up to a factor of $\textrm{poly}(\log n, 1/\epsilon)$.