Pith Number

pith:WOMKSVL5

pith:2011:WOMKSVL55OAMDQ2BIXK6JUMURP

not attested not anchored not stored refs pending

The Complexity of the Empire Colouring Problem

Andrew R. A. McGrae, Michele Zito

arxiv:1109.2162 v1 · 2011-09-09 · cs.CC

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{WOMKSVL55OAMDQ2BIXK6JUMURP}

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	2026-05-18T00:14:11.654633Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

b398a9557deb80c1c34145d5e4d1948bde9cca46e5a9547738789cb0480b0167

Aliases

arxiv: 1109.2162 · arxiv_version: 1109.2162v1 · doi: 10.48550/arxiv.1109.2162 · pith_short_12: WOMKSVL55OAM · pith_short_16: WOMKSVL55OAMDQ2B · pith_short_8: WOMKSVL5

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/WOMKSVL55OAMDQ2BIXK6JUMURP \
  | 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: b398a9557deb80c1c34145d5e4d1948bde9cca46e5a9547738789cb0480b0167

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "7c5e1f0b612900392596166222ac947c7c84d1c671c4cec49876e9e557b3842b",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "cs.CC",
    "submitted_at": "2011-09-09T21:13:39Z",
    "title_canon_sha256": "fc3a01eec862c9c3623a74a8d732acb01b1d5e882ceacae7f2931150adb54c96"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1109.2162",
    "kind": "arxiv",
    "version": 1
  }
}