Pith Number

pith:FIDY6VD4

pith:2012:FIDY6VD4S7FMW745ZZCQJRMLXZ

not attested not anchored not stored refs pending

A note on the history of the four-colour conjecture

Brendan D. McKay

arxiv:1201.2852 v2 · 2012-01-13 · math.CO · math.HO

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{FIDY6VD4S7FMW745ZZCQJRMLXZ}

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	2026-05-18T04:01:50.696147Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

2a078f547c97cacb7f9dce4504c58bbe7047d54287af5c9af6e44cc1217c5d67

Aliases

arxiv: 1201.2852 · arxiv_version: 1201.2852v2 · doi: 10.48550/arxiv.1201.2852 · pith_short_12: FIDY6VD4S7FM · pith_short_16: FIDY6VD4S7FMW745 · pith_short_8: FIDY6VD4

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/FIDY6VD4S7FMW745ZZCQJRMLXZ \
  | 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: 2a078f547c97cacb7f9dce4504c58bbe7047d54287af5c9af6e44cc1217c5d67

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "86e35d953d17d1d41ef206ee144967177668edbe84ff2ac31d045c7e39b208cc",
    "cross_cats_sorted": [
      "math.HO"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.CO",
    "submitted_at": "2012-01-13T14:53:40Z",
    "title_canon_sha256": "fd0d3204b6e8570b0efcc4053a34ff6dfd5c0e045a37929174627d343f25d8f8"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1201.2852",
    "kind": "arxiv",
    "version": 2
  }
}