Pith Number

pith:X7MPNBYE

pith:2019:X7MPNBYELVZXOSSXFCNHUIVKUD

not attested not anchored not stored refs pending

MSO+nabla is undecidable

Edon Kelmendi, Micha{\l} Skrzypczak, Miko{\l}aj Boja\'nczyk

arxiv:1901.06900 v2 · 2019-01-21 · cs.LO

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{X7MPNBYELVZXOSSXFCNHUIVKUD}

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	2026-05-17T23:47:35.813123Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

bfd8f687045d73774a57289a7a22aaa0d8fa91b30df111e23a53928af34ded1d

Aliases

arxiv: 1901.06900 · arxiv_version: 1901.06900v2 · doi: 10.48550/arxiv.1901.06900 · pith_short_12: X7MPNBYELVZX · pith_short_16: X7MPNBYELVZXOSSX · pith_short_8: X7MPNBYE

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/X7MPNBYELVZXOSSXFCNHUIVKUD \
  | 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: bfd8f687045d73774a57289a7a22aaa0d8fa91b30df111e23a53928af34ded1d

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "b4be98fa1d01ad9896e5805159fd62590fcbe340105abb9e0f7604c062d55562",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "cs.LO",
    "submitted_at": "2019-01-21T12:13:48Z",
    "title_canon_sha256": "1e58943657182dd3f1126e9cfd24a254f7812268c17231ea85de059925108f9a"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1901.06900",
    "kind": "arxiv",
    "version": 2
  }
}