Pith Number

pith:CH3FZY4D

pith:2015:CH3FZY4DMTKPQ2PERUP4LGW6VP

not attested not anchored not stored refs pending

On Cremona contractibility of unions of lines in the plane

Alberto Calabri, Ciro Ciliberto

arxiv:1503.05850 v2 · 2015-03-19 · math.AG

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{CH3FZY4DMTKPQ2PERUP4LGW6VP}

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	2026-05-18T00:48:46.352489Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

11f65ce38364d4f869e48d1fc59adeabd1b8bc3d8c61e05d82fe7c58a7f08551

Aliases

arxiv: 1503.05850 · arxiv_version: 1503.05850v2 · doi: 10.48550/arxiv.1503.05850 · pith_short_12: CH3FZY4DMTKP · pith_short_16: CH3FZY4DMTKPQ2PE · pith_short_8: CH3FZY4D

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/CH3FZY4DMTKPQ2PERUP4LGW6VP \
  | 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: 11f65ce38364d4f869e48d1fc59adeabd1b8bc3d8c61e05d82fe7c58a7f08551

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "b614e2c77c3cfd35a73afa7b275f3ef1ff4611cf0cafd0fcee102e7007b9b22b",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.AG",
    "submitted_at": "2015-03-19T17:28:31Z",
    "title_canon_sha256": "729e7c46e5e1d2839ecdca4d7ee01fe002d746a8236f4a25c3a1da7b79242f64"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1503.05850",
    "kind": "arxiv",
    "version": 2
  }
}