Pith Number

pith:PBPRGT7U

pith:2010:PBPRGT7UCXN7BLJMYEQNSI5ONF

not attested not anchored not stored refs pending

The extender algebra and $\Sigma^2_1$-absoluteness

Ilijas Farah

arxiv:1005.4193 v3 · 2010-05-23 · 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{PBPRGT7UCXN7BLJMYEQNSI5ONF}

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	2026-05-18T01:08:27.718251Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

785f134ff415dbf0ad2cc120d923ae6948823952bd65405b67bdb84bdc9b979a

Aliases

arxiv: 1005.4193 · arxiv_version: 1005.4193v3 · doi: 10.48550/arxiv.1005.4193 · pith_short_12: PBPRGT7UCXN7 · pith_short_16: PBPRGT7UCXN7BLJM · pith_short_8: PBPRGT7U

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/PBPRGT7UCXN7BLJMYEQNSI5ONF \
  | 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: 785f134ff415dbf0ad2cc120d923ae6948823952bd65405b67bdb84bdc9b979a

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "7cc74867dc10d2bf6446bad0b57aa0743d3b36234312dcba578322309e9c8838",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.LO",
    "submitted_at": "2010-05-23T11:38:35Z",
    "title_canon_sha256": "b3c37328d4c47fc8c82dac4b774d627ec7c2d3112543b660fcb8b69d6508d833"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1005.4193",
    "kind": "arxiv",
    "version": 3
  }
}