A page can change. Its edition should not.

The ordinary notebook address points to the current explanatory text. An edition address includes a named snapshot and continues to serve that snapshot’s content when the living notebook is revised.

What is preserved#

• The notebook and chapter identity.
• The chapter introduction, text, figures and structured content.
• The reference list and its recorded resource links.
• The edition date and a SHA-256 content fingerprint.

Checking a citation#

Download the page’s citation metadata to retrieve the canonical JSON payload and the expected SHA-256 value. Recomputing the digest of that payload checks content identity. It cannot establish the truth of the content or the continued availability of an external source.

A correction creates a successor#

A living page can improve its explanation or correct a mistaken release description. The earlier edition should continue to identify what a reader could cite at that time. This makes it possible to distinguish an editorial correction from a changed research artifact, and to explain why two quotations or references differ.

Verify a downloaded citation record#

import hashlib
import json
from pathlib import Path

record = json.loads(Path("citation.json").read_text(encoding="utf-8"))
payload = record["canonicalPayload"].encode("utf-8")
actual = hashlib.sha256(payload).hexdigest()
if actual != record["sha256"]:
    raise SystemExit("Content fingerprint does not match")
print("Verified:", record["edition"], actual)

Hash the supplied canonicalPayload string exactly, without pretty-printing it or converting its line endings. The structured payload is also provided for inspection. The comparison verifies consistency with the expected digest in that record; independently retained metadata or an archived copy is needed if you want a reference beyond the current host.

Preservation extends beyond the website#

Versioned local URLs and checksums make these notebooks citable and inspectable, but continued access still depends on hosting and retained editions. A separately archived release could provide an additional preservation location. No notebook DOI or independent repository deposit is implied until such a deposit has actually been made.