Pith Number

pith:NNUVBM3O

pith:2012:NNUVBM3O77ASEIJ57BXRADDZHA

not attested not anchored not stored refs pending

The existence of fractional repetition codes

Toni Ernvall

arxiv:1201.3547 v1 · 2012-01-13 · math.CO · cs.DM

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{NNUVBM3O77ASEIJ57BXRADDZHA}

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	2026-05-18T04:04:28.965573Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

6b6950b36effc122213df86f100c793839728093816d314eeb55f4e68fa75724

Aliases

arxiv: 1201.3547 · arxiv_version: 1201.3547v1 · doi: 10.48550/arxiv.1201.3547 · pith_short_12: NNUVBM3O77AS · pith_short_16: NNUVBM3O77ASEIJ5 · pith_short_8: NNUVBM3O

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/NNUVBM3O77ASEIJ57BXRADDZHA \
  | 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: 6b6950b36effc122213df86f100c793839728093816d314eeb55f4e68fa75724

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "cb5dc7560169762e76553717e0054f7ad86f0fe3e5edb81521afdd87f07f94fd",
    "cross_cats_sorted": [
      "cs.DM"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.CO",
    "submitted_at": "2012-01-13T08:58:30Z",
    "title_canon_sha256": "4b14747945ae792e3ba1074c2bf6a37ae720495ca661aee0fdfee4f016b8127b"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1201.3547",
    "kind": "arxiv",
    "version": 1
  }
}