Pith Number

pith:DS3J5UX7

pith:2019:DS3J5UX75LVN35N7ZNE7X3N2B4

not attested not anchored not stored refs pending

Elementary subgroups of the free group are free factors - a new proof

Chlo\'e Perin

arxiv:1903.05876 v1 · 2019-03-14 · math.LO · math.GR

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{DS3J5UX75LVN35N7ZNE7X3N2B4}

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	2026-05-17T23:51:15.879181Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

1cb69ed2ffeaeaddf5bfcb49fbedba0f2e48d4971b2d7e72992148313614ed0f

Aliases

arxiv: 1903.05876 · arxiv_version: 1903.05876v1 · doi: 10.48550/arxiv.1903.05876 · pith_short_12: DS3J5UX75LVN · pith_short_16: DS3J5UX75LVN35N7 · pith_short_8: DS3J5UX7

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/DS3J5UX75LVN35N7ZNE7X3N2B4 \
  | 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: 1cb69ed2ffeaeaddf5bfcb49fbedba0f2e48d4971b2d7e72992148313614ed0f

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "b58c6480746210f399e8e1e71c571552c1bb4d4cad83f3ea392e6d6417bb2a20",
    "cross_cats_sorted": [
      "math.GR"
    ],
    "license": "http://creativecommons.org/licenses/by-nc-sa/4.0/",
    "primary_cat": "math.LO",
    "submitted_at": "2019-03-14T09:48:24Z",
    "title_canon_sha256": "1a8e0a5ab81a490034d664b26b6e6a4236ab32843b8106986cc980f8439ae270"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1903.05876",
    "kind": "arxiv",
    "version": 1
  }
}