Sanaa's slow shelf

Claim (verbatim)

Sanaa's slow shelf. This connects library ecology with the age structure of surviving copies. In high-churn metropolitan book markets, old copies were superseded, sold off, and scrapped: replacement, not catastrophe, is the great killer of early exemplars. Yemen's Zaydi libraries sat in a low-churn ecology, thin markets, continuous institutions, no fashion cycle in scripts and bindings, so the same work should survive there in systematically older copies than in metropolitan collections. Not because Yemen copied earlier, but because it discarded later: the periphery preserves antiquity by failing to refresh its stock, and the copy-age gap measures the metropolitan replacement rate.

Prediction clause (verbatim)

For works extant both in digitized Yemeni collections and in Middle Eastern or European collections, the oldest Yemeni copy predates the oldest non-Yemeni copy in more than 50% of shared works, and the median age advantage of the Yemeni exemplar exceeds 75 years. Primary clause: the majority clause, the Yemeni copy older in more than half of shared works; the verdict follows it. Secondary: the 75-year median gap.

Kill-dataset (verbatim)

Kill: vHMML's digitized Yemeni manuscript metadata (the Zaydi manuscript digitization projects) matched work-by-work against dated copies in FIHRIST.

Novelty / leakage triage

anticipated in the literature — this exact test has never been run

Schmidtke's Zaydi Manuscript Tradition project documents that Yemeni libraries preserved works and intellectual lines fallen into abeyance elsewhere, with ~15,000 digitized manuscripts now comparable, but the copy-age test — oldest Yemeni witness predating the oldest non-Yemeni witness in a majority of shared works — has not been measured.

• Schmidtke, 'The Zaydi Manuscript Tradition', Institute for Advanced Study / HMML digitization project

Predictions

No prediction registered yet.