Pith Number

pith:FXAK5J74

pith:2016:FXAK5J743Y6EGSRHTKMKTUDPIM

not attested not anchored not stored refs pending

The reverse mathematics of the Tietze extension theorem

Paul Shafer

arxiv:1602.05398 v1 · 2016-02-17 · 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{FXAK5J743Y6EGSRHTKMKTUDPIM}

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	2026-05-18T01:20:28.329726Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

2dc0aea7fcde3c434a279a98a9d06f4311832c708fa511051da6867f10939b72

Aliases

arxiv: 1602.05398 · arxiv_version: 1602.05398v1 · doi: 10.48550/arxiv.1602.05398 · pith_short_12: FXAK5J743Y6E · pith_short_16: FXAK5J743Y6EGSRH · pith_short_8: FXAK5J74

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/FXAK5J743Y6EGSRHTKMKTUDPIM \
  | 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: 2dc0aea7fcde3c434a279a98a9d06f4311832c708fa511051da6867f10939b72

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "acb97ccb2358a7f154a64c40076653ad6443dde46465a09583a2da71a053ea41",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.LO",
    "submitted_at": "2016-02-17T13:11:40Z",
    "title_canon_sha256": "e5b2783aced3a8e8d1b778decef633dd89377c1efa49ee6336f38759932a52b4"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1602.05398",
    "kind": "arxiv",
    "version": 1
  }
}