Pith Number

pith:YWDGY3NE

pith:2012:YWDGY3NENEZKCD7OIIMX5W4CTT

not attested not anchored not stored refs pending

A Note on Undecidability of Observation Consistency for Non-Regular Languages

Tom\'a\v{s} Masopust

arxiv:1201.1754 v1 · 2012-01-09 · cs.SY · cs.FL

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{YWDGY3NENEZKCD7OIIMX5W4CTT}

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	2026-05-18T04:04:55.798871Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

c5866c6da46932a10fee42197edb829cd7e6f53682bcd41a500df9b2263497dd

Aliases

arxiv: 1201.1754 · arxiv_version: 1201.1754v1 · doi: 10.48550/arxiv.1201.1754 · pith_short_12: YWDGY3NENEZK · pith_short_16: YWDGY3NENEZKCD7O · pith_short_8: YWDGY3NE

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/YWDGY3NENEZKCD7OIIMX5W4CTT \
  | 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: c5866c6da46932a10fee42197edb829cd7e6f53682bcd41a500df9b2263497dd

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "4da0998acdb417042e796af18663ccf2dc6aceea238e5f69df939228f3b68c5d",
    "cross_cats_sorted": [
      "cs.FL"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "cs.SY",
    "submitted_at": "2012-01-09T13:40:34Z",
    "title_canon_sha256": "49d832ec176aed8daf1a7cfdedc00acb718d0a790cc566adf5f97d370ad70535"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1201.1754",
    "kind": "arxiv",
    "version": 1
  }
}