Pith Number

pith:GO72OBO4

pith:2021:GO72OBO4A6RLZW5A4ZCF5KDELZ

not attested not anchored not stored refs pending

Nodal quintic surfaces and lines on cubic fourfolds

Daniel Huybrechts, with an appendix by John Ottem

arxiv:2108.10532 v2 · 2021-08-24 · 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{GO72OBO4A6RLZW5A4ZCF5KDELZ}

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.

Cited by

1 paper in Pith

Chow groups of surfaces of lines in cubic fourfolds

Receipt and verification

First computed	2026-07-05T05:43:08.253653Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

33bfa705dc07a2bcdba0e6445ea8645e6188adab64e7754be3fc114a743a24e1

Aliases

arxiv: 2108.10532 · arxiv_version: 2108.10532v2 · doi: 10.48550/arxiv.2108.10532 · pith_short_12: GO72OBO4A6RL · pith_short_16: GO72OBO4A6RLZW5A · pith_short_8: GO72OBO4

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/GO72OBO4A6RLZW5A4ZCF5KDELZ \
  | 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: 33bfa705dc07a2bcdba0e6445ea8645e6188adab64e7754be3fc114a743a24e1

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "d4d691d6702f9754a43ef5fdcc7d8c035f2892256bed9d75257a763ed06e124f",
    "cross_cats_sorted": [],
    "license": "http://creativecommons.org/licenses/by/4.0/",
    "primary_cat": "math.AG",
    "submitted_at": "2021-08-24T05:43:26Z",
    "title_canon_sha256": "b73085b6f2c6d998576711ca04fcedac0f7e0ca5efd9313a88c53acc52edd1b8"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2108.10532",
    "kind": "arxiv",
    "version": 2
  }
}