Pith Number

pith:O4XZAMMQ

pith:2008:O4XZAMMQFMSEXXOU5FOVN4AT4J

not attested not anchored not stored refs pending

On the decidability of semigroup freeness

Francois Nicolas, Julien Cassaigne

arxiv:0808.3112 v4 · 2008-08-22 · 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{O4XZAMMQFMSEXXOU5FOVN4AT4J}

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	2026-05-18T03:56:24.670844Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

772f9031902b244bddd4e95d56f013e26793ad9dad219db34fd38aaebe657f71

Aliases

arxiv: 0808.3112 · arxiv_version: 0808.3112v4 · doi: 10.48550/arxiv.0808.3112 · pith_short_12: O4XZAMMQFMSE · pith_short_16: O4XZAMMQFMSEXXOU · pith_short_8: O4XZAMMQ

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/O4XZAMMQFMSEXXOU5FOVN4AT4J \
  | 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: 772f9031902b244bddd4e95d56f013e26793ad9dad219db34fd38aaebe657f71

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "d617780364ab817db5c685810c8ccbb2b5b7a598dda526549f4f2db32f40dcf8",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "cs.DM",
    "submitted_at": "2008-08-22T16:37:29Z",
    "title_canon_sha256": "e9b8867d79daa92a962de0f0a8729cc50cbe71e8e93314e26d4322d29c41e6bf"
  },
  "schema_version": "1.0",
  "source": {
    "id": "0808.3112",
    "kind": "arxiv",
    "version": 4
  }
}