Alon, Matias and Szegedy: frequency moments with streaming memory

What changed

Alon, Matias and Szegedy developed a randomized small-memory estimator for the second frequency moment and a framework relating one-pass frequency-moment approximation to space complexity.

Scientific scope

Alon, Matias and Szegedy developed a randomized small-memory estimator for the second frequency moment and a framework relating one-pass frequency-moment approximation to space complexity. The F2 streaming estimator uses four-wise independent signs and independent averaging/amplification. Pairwise independence suffices for its mean, but not the stated variance bound. Memory depends on accuracy, failure probability and the size of the stream/universe; this is neither exact nor deterministic sublinear counting. The source read is a 2002 author manuscript representing the 1996/1999 publication lineage, whose complete revision equivalence is unresolved. Adaptive adversarial-query guarantees and later sketch results are separate.

Evidence

Source-linked, scoped account of the original work. The published scope states the scientific assumptions and remaining verification limits. WRS has not independently certified the full proof, experimental result or system benchmark.

Contributors

Noga Alon · SCIENCE: Original source-listed scientific author of this scoped work; byline does not determine effort fractions.
Yossi Matias · SCIENCE: Original source-listed scientific author of this scoped work; byline does not determine effort fractions.
Mario Szegedy · SCIENCE: Original source-listed scientific author of this scoped work; byline does not determine effort fractions.

Provisional WRS assessment, edition 2026-10-16.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.

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