Pith Number

pith:7TBHFZZI

pith:2011:7TBHFZZIMJGRI2KG6BVW7ESSHX

not attested not anchored not stored refs pending

The equal tangents problem

S. Tabachnikov

arxiv:1102.5577 v1 · 2011-02-28 · math.MG

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{7TBHFZZIMJGRI2KG6BVW7ESSHX}

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	2026-05-18T04:27:46.541033Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

fcc272e728624d146946f06b6f92523dd97dd7269a36f47250e07f4884c2dfbb

Aliases

arxiv: 1102.5577 · arxiv_version: 1102.5577v1 · doi: 10.48550/arxiv.1102.5577 · pith_short_12: 7TBHFZZIMJGR · pith_short_16: 7TBHFZZIMJGRI2KG · pith_short_8: 7TBHFZZI

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/7TBHFZZIMJGRI2KG6BVW7ESSHX \
  | 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: fcc272e728624d146946f06b6f92523dd97dd7269a36f47250e07f4884c2dfbb

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "131ccafad2d0191f560fe38dd3ba9d876bfb06492ea01fb63aef523e897a7ab8",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.MG",
    "submitted_at": "2011-02-28T02:41:03Z",
    "title_canon_sha256": "e2cc6ff1d83e2812359a731b55a9e9affcb4a23460c095b851c6828d02c234eb"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1102.5577",
    "kind": "arxiv",
    "version": 1
  }
}