Representation study — bitmap vs selection vector

Status: OPEN — pre-registered; two of ≥3 ISAs collected. The full study needs entry-referenced ledger data across ≥3 ISAs and ≥5 µarchs (Charter §6.2 / Survey §11.3 #3); registered so far: apple-m2-mba (NEON, indicative slice) and intel-i9-9900k (AVX2, committed compare entries, run 20260805-f7b016f85d08). The cross-µarch analysis and conclusion remain PENDING hardware (R-06 / REQ-LEDGER-012). No numbers here are invented (Charter T2).

This directory is the M9 charter deliverable — the bitmap-vs-selvec representation question, its pre-registered method, the data collected so far, and the analysis/conclusion (open):

File	Contents
question.md	The research question and hypotheses
method.md	Pre-registered protocol + decision rule (run before looking at cross-µarch data)
entries.md	Data: the apple-m2 (NEON) indicative slice and the committed intel-coffee-lake (AVX2) entries (run 20260805-f7b016f85d08); remaining µarchs toward ≥3 ISAs / ≥5 µarchs pending
analysis.md	Analysis of the slice; what the full study still requires
conclusion.md	OPEN — the ≥3-ISA/≥5-µarch bar is unmet (2 ISAs / 2 µarchs registered)

Gate: releases/gates/M9.md.