A Fast Binary Splitting Approach for Non-Adaptive Learning of Erdos--Renyi Graphs

arXiv:2511.17240v3 Announce Type: replace-cross Abstract: We study the problem of learning an unknown graph via group queries on node subsets, where each query reports whether at least one edge is present among the queried nodes. In general, learning arbitrary graphs with n nodes and k edges is hard in the non-adaptive setting, requiring Omegaig(min{k^2log n,,n^2}ig) tests even when a small error probability is allowed. We focus on learning Erdos--Renyi (ER) graphs GsimER(n,q) in the non-adaptive setting, where the expected number of edges is ar{k}=qinom{n}{2}, and we aim to design an efficient testing--decoding scheme, namely, a non-adaptive test design together with a decoding algorithm, achieving asymptotically vanishing error probability. Prior work (Li--Fresacher--Scarlett, NeurIPS 2019) presents a testing--decoding scheme that attains an order-optimal number of tests O(ar{k}log n) but incurs Omega(n^2) decoding time, whereas their proposed sublinear-time algorithm incurs an extra (log ar{k})(log n) factor in the number of tests. We extend the binary splitting approach, recently developed for non-adaptive group testing, to the ER graph learning setting, and prove that the edge set can be recovered with high probability using O(ar{k}log n) tests while attaining decoding time O(ar{k}^{1+elta}log n) for any fixed elta>0.

Source: arXiv cs.LG | 2026-07-08