Pith Number

pith:XKAPLFC7

pith:2009:XKAPLFC77PR6LEEGDYAWUVMJCH

not attested not anchored not stored refs pending

Approximating classifying spaces by smooth projective varieties

Torsten Ekedahl

arxiv:0905.1538 v1 · 2009-05-11 · math.AG · math.AT

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{XKAPLFC77PR6LEEGDYAWUVMJCH}

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	2026-07-04T15:42:21.930808Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

ba80f5945ffbe3e590861e016a558911e807df6c58a260c20e48edc86aa649f1

Aliases

arxiv: 0905.1538 · arxiv_version: 0905.1538v1 · doi: 10.48550/arxiv.0905.1538 · pith_short_12: XKAPLFC77PR6 · pith_short_16: XKAPLFC77PR6LEEG · pith_short_8: XKAPLFC7

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/XKAPLFC77PR6LEEGDYAWUVMJCH \
  | 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: ba80f5945ffbe3e590861e016a558911e807df6c58a260c20e48edc86aa649f1

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "97d22014590918948e7a931642bf7f1278bfea69fa9a5e240821a29d63d9f913",
    "cross_cats_sorted": [
      "math.AT"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.AG",
    "submitted_at": "2009-05-11T04:27:22Z",
    "title_canon_sha256": "c03323b0e1f3d339ae4e6ba84d0eb66150eaeba3b65806fd2d80332a78b01dc6"
  },
  "schema_version": "1.0",
  "source": {
    "id": "0905.1538",
    "kind": "arxiv",
    "version": 1
  }
}