Pith Number

pith:PX3BKTX2

pith:2011:PX3BKTX26ZMWW5L2WHDH3WXORZ

not attested not anchored not stored refs pending

Discovery of the Expansion of the Universe

Sidney van den Bergh

arxiv:1108.0709 v2 · 2011-08-02 · physics.hist-ph · astro-ph.CO

Open paper page JSON Open Graph Bundle Merged state Verified badge What is a Pith Number?

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{PX3BKTX26ZMWW5L2WHDH3WXORZ}

Prints a linked badge after your title and injects PDF metadata. Compiles on arXiv. Learn more · Embed verified badge

Record completeness

1 Bitcoin timestamp

2 Internet Archive

3 Author claim open · sign in to claim

4 Citations open

5 Replications open

✓ Portable graph bundle live · download bundle · merged state

The bundle contains the canonical record plus signed events. A mirror can host it anywhere and recompute the same current state with the deterministic merge algorithm.

Receipt and verification

First computed	2026-05-18T04:13:46.739854Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

7df6154efaf6596b757ab1c67ddaee8e5afd14203ada8a09bcd913dba7b415b4

Aliases

arxiv: 1108.0709 · arxiv_version: 1108.0709v2 · doi: 10.48550/arxiv.1108.0709 · pith_short_12: PX3BKTX26ZMW · pith_short_16: PX3BKTX26ZMWW5L2 · pith_short_8: PX3BKTX2

Agent API

Resolver JSON Graph JSON Events JSON Schema Signing key

Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/PX3BKTX26ZMWW5L2WHDH3WXORZ \
  | jq -c '.canonical_record' \
  | python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
# expect: 7df6154efaf6596b757ab1c67ddaee8e5afd14203ada8a09bcd913dba7b415b4

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "7a3032db3d3c40bbf3e094386973f2cf9b514ad704ba51f8b9ae1a719a69184b",
    "cross_cats_sorted": [
      "astro-ph.CO"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "physics.hist-ph",
    "submitted_at": "2011-08-02T22:59:48Z",
    "title_canon_sha256": "dcd1768ac20883d8b3d9918fcaa389afb4475f763d83d1f979d41742327c2d2c"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1108.0709",
    "kind": "arxiv",
    "version": 2
  }
}