D-0008 · When one book counts as before another

Only when B's whole window ends before A's window begins. When the windows overlap, the time check says "the dates cannot tell" and flags nothing.

The options on the table

• Only when the windows do not touch; overlap means the dates cannot tell (chosen)
• Compare the middles of the two windows
• Compare when each book was started
• Compare when each book was finished

Why

A check that accuses a sefer of quoting a later sefer must be able to prove it. When two windows overlap — Rashi (4825–4875) and Tosafos (about 4860–5060) — the dates alone cannot say which came first, so the check stays silent rather than guess. Comparing the middles of the windows would turn a guess into what looks like a fact.

EASY — the windows do not touch
  Rambam, Mishneh Torah  |====|                          ~4930–4940
  Shulchan Aruch                          |====|         ~5310–5323
  → the Rambam is first.

HARD — the windows overlap
  Rashi            |==========|                          4825–4875
  Tosafos                |====================|          ~4860–5060
  → the dates cannot tell; the check flags nothing.

What rests on this

• D-0009 · The Zohar's date

Generated from the register (docs/decisions/0008-before.md). A changed value is recorded as a new entry; the old one is never overwritten.