E055: Mertens function walk

Preview figure for E055
Preview figure for E055

Tags: number-theory, quantitative-exploration, visualization, arithmetic-functions, mobius, summatory, model-checking See: Valid Tags.

Highlights

  • Plot \(M(x)\) and scaled variants such as \(M(x)/\sqrt{x}\).

  • Compare qualitative behavior to a simple random-walk heuristic (without overclaiming).

Goal

Build intuition for summatory Möbius behavior and typical fluctuation scales.

Background (quick refresher)

Research question

What does \(M(x)/\sqrt{x}\) look like numerically over moderate ranges?

Method

  • Compute \(\mu(n)\) up to \(N\) and cumulative sums \(M(x)\).

  • Plot \(M(x)\) and \(M(x)/\sqrt{x}\); optionally add moving-window statistics.

How to run

  • make run EXP=e055

  • uv run python -m mathxlab.experiments.e055

Outputs

This experiment follows the standard output contract:

  • out/e055/figures/ — generated figures (PNG)

  • out/e055/report.md — short narrative report

  • out/e055/manifest.json — snapshot metadata for the gallery

Published run snapshot

If this experiment is included in the docs gallery, include the published snapshot (report + params).

  • n_max: 300000

  • max |M(x)| in range: 235

Figures:

  • fig_01_mertens.png

  • fig_02_mertens_scaled.png

params.json (snapshot)
{
  "n_max": 300000
}

References

See Tenenbaum [2015], Odlyzko and te Riele [1985].