Separating Adaptive Streaming from Oblivious Streaming

TL;DR

This paper demonstrates a fundamental difference between oblivious and adversarially-robust streaming algorithms, showing that robust algorithms require polynomial space while oblivious ones only need polylogarithmic space, resolving a key open question.

Contribution

It provides the first known separation between oblivious and adversarially-robust streaming models, establishing a fundamental complexity distinction.

Findings

Adversarially-robust streaming algorithms require polynomial space.

Classical oblivious streaming algorithms operate with polylogarithmic space.

This work resolves a major open question in adversarial robust streaming.

Abstract

We present a streaming problem for which every adversarially-robust streaming algorithm must use polynomial space, while there exists a classical (oblivious) streaming algorithm that uses only polylogarithmic space. This is the first separation between oblivious streaming and adversarially-robust streaming, and resolves one of the central open questions in adversarial robust streaming.