Pith Number

pith:PEWYX4PY

pith:2008:PEWYX4PYLB2JNSCUBQ23E5DQ5V

not attested not anchored not stored refs pending

d-collapsibility is NP-complete for d greater or equal to 4

Martin Tancer

arxiv:0808.1991 v2 · 2008-08-14 · math.CO

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{PEWYX4PYLB2JNSCUBQ23E5DQ5V}

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	2026-05-18T02:24:57.092482Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

792d8bf1f8587496c8540c35b27470ed4d6fabb7aa860ddaad667217c1507c1f

Aliases

arxiv: 0808.1991 · arxiv_version: 0808.1991v2 · doi: 10.48550/arxiv.0808.1991 · pith_short_12: PEWYX4PYLB2J · pith_short_16: PEWYX4PYLB2JNSCU · pith_short_8: PEWYX4PY

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/PEWYX4PYLB2JNSCUBQ23E5DQ5V \
  | 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: 792d8bf1f8587496c8540c35b27470ed4d6fabb7aa860ddaad667217c1507c1f

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "c59451dd5eb1972066b15f75657fdccce1cefc025aa8ad76a0ba6bfe820f548b",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.CO",
    "submitted_at": "2008-08-14T13:29:59Z",
    "title_canon_sha256": "e37b5ef26f9f63abd2ecc500cfe3bd386aa0793c1449fff59ee10059307fcd89"
  },
  "schema_version": "1.0",
  "source": {
    "id": "0808.1991",
    "kind": "arxiv",
    "version": 2
  }
}