Pith Number

pith:AAJNNE3K

pith:2009:AAJNNE3KRRM4LH4S2B2USDYFCD

not attested not anchored not stored refs pending

Second cohomology groups and finite covers

David M. Evans, Elisabetta Pastori

arxiv:0909.0366 v2 · 2009-09-02 · math.GR · math.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{AAJNNE3KRRM4LH4S2B2USDYFCD}

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	2026-05-18T04:26:02.544218Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

0012d6936a8c59c59f92d075490f0510efa6712d3759eb4eb5f26903ec138989

Aliases

arxiv: 0909.0366 · arxiv_version: 0909.0366v2 · doi: 10.48550/arxiv.0909.0366 · pith_short_12: AAJNNE3KRRM4 · pith_short_16: AAJNNE3KRRM4LH4S · pith_short_8: AAJNNE3K

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/AAJNNE3KRRM4LH4S2B2USDYFCD \
  | 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: 0012d6936a8c59c59f92d075490f0510efa6712d3759eb4eb5f26903ec138989

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "73ee2cf50eb7355c60f690d502d4d9499a9f6a885a7a89248248849a073dc79b",
    "cross_cats_sorted": [
      "math.LO"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.GR",
    "submitted_at": "2009-09-02T14:03:28Z",
    "title_canon_sha256": "815b6962c078e5bff8f3592a6d7c1fb1291d8a5acb4c58a35535458807abfc7b"
  },
  "schema_version": "1.0",
  "source": {
    "id": "0909.0366",
    "kind": "arxiv",
    "version": 2
  }
}