Nearly Space-Optimal Graph and Hypergraph Sparsification in Insertion-Only Data Streams
Vincent Cohen-Addad, David P. Woodruff, Shenghao Xie, Samson Zhou
TL;DR
The paper addresses sparsification of graphs and hypergraphs in insertion-only data streams, aiming to preserve energy-like quadratic forms for all vectors while using near-minimal space. It develops online and streaming algorithms that yield $(1+\varepsilon)$-spectral sparsifiers for graphs and hypergraphs, along with min-cut approximations, adversarially robust variants, and sliding-window adaptations; all achieve space bounds essentially matching offline sample complexities up to poly-logarithmic factors. The approach hinges on online leverage-score based sampling, gamma-balanced weight assignments, and a merge-and-reduce coreset framework to control error accumulation and memory usage, with update times polynomial in the graph size. These results significantly reduce space overhead compared to prior streaming and online work, enabling practical sparsification on massive, rapidly arriving data while supporting robust and time-sensitive streaming settings. The work also connects to concurrent results in online/dynamic sparsification, and provides a unified framework for extending sparsification guarantees to adversarial and sliding-window models, broadening applicability in real-time analytics and scalable graph-based learning.
Abstract
We study the problem of graph and hypergraph sparsification in insertion-only data streams. The input is a hypergraph $H=(V, E, w)$ with $n$ nodes, $m$ hyperedges, and rank $r$, and the goal is to compute a hypergraph $\widehat{H}$ that preserves the energy of each vector $x \in \mathbb{R}^n$ in $H$, up to a small multiplicative error. In this paper, we give a streaming algorithm that achieves a $(1+\varepsilon)$-approximation, using $\frac{rn}{\varepsilon^2} \log^2 n \log r \cdot\text{poly}(\log \log m)$ bits of space, matching the sample complexity of the best known offline algorithm up to $\text{poly}(\log \log m)$ factors. Our approach also provides a streaming algorithm for graph sparsification that achieves a $(1+\varepsilon)$-approximation, using $\frac{n}{\varepsilon^2} \log n \cdot\text{poly}(\log\log n)$ bits of space, improving the current bound by $\log n$ factors. Furthermore, we give a space-efficient streaming algorithm for min-cut approximation. Along the way, we present an online algorithm for $(1+\varepsilon)$-hypergraph sparsification, which is optimal up to poly-logarithmic factors. As a result, we achieve $(1+\varepsilon)$-hypergraph sparsification in the sliding window model, with space optimal up to poly-logarithmic factors. Lastly, we give an adversarially robust algorithm for hypergraph sparsification using $\frac{n}{\varepsilon^2} \cdot\text{poly}(r, \log n, \log r, \log \log m)$ bits of space.
