Pith Number

pith:WBEXKAQF

pith:2019:WBEXKAQFYQFTJBDLYCHLGKTF67

not attested not anchored not stored refs pending

Two variations on the periscope theorem

Serge Tabachnikov

arxiv:1908.08359 v1 · 2019-08-22 · math.DG · math.SG

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{WBEXKAQFYQFTJBDLYCHLGKTF67}

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	2026-07-05T00:48:17.918275Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

b049750205c40b34846bc08eb32a65f7e2f41101f0ee939368d960fce7c1191b

Aliases

arxiv: 1908.08359 · arxiv_version: 1908.08359v1 · doi: 10.48550/arxiv.1908.08359 · pith_short_12: WBEXKAQFYQFT · pith_short_16: WBEXKAQFYQFTJBDL · pith_short_8: WBEXKAQF

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/WBEXKAQFYQFTJBDLYCHLGKTF67 \
  | 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: b049750205c40b34846bc08eb32a65f7e2f41101f0ee939368d960fce7c1191b

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "868883247efb4881042dc829a0ecc4a052d6d149321e147136c672f1b8074c50",
    "cross_cats_sorted": [
      "math.SG"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.DG",
    "submitted_at": "2019-08-22T13:27:39Z",
    "title_canon_sha256": "2503ae209eec54cfbbbf67ab61410b883ca1b14813e1ae062ee051ffd6c86190"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1908.08359",
    "kind": "arxiv",
    "version": 1
  }
}