Pith Number

pith:4NQATKKJ

pith:2020:4NQATKKJFHEANZ56II74L7OUZ5

not attested not anchored not stored refs pending

On the Complexity of the Universality and Inclusion Problems for Unambiguous Context-Free Grammars

Lorenzo Clemente (University of Warsaw)

arxiv:2008.04667 v1 · 2020-08-07 · cs.FL

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{4NQATKKJFHEANZ56II74L7OUZ5}

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	2026-07-05T01:26:27.718093Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

e36009a94929c806e7be423fc5fdd4cf487ec466f2a1ae1a7438eb835495fe0f

Aliases

arxiv: 2008.04667 · arxiv_version: 2008.04667v1 · doi: 10.48550/arxiv.2008.04667 · pith_short_12: 4NQATKKJFHEA · pith_short_16: 4NQATKKJFHEANZ56 · pith_short_8: 4NQATKKJ

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/4NQATKKJFHEANZ56II74L7OUZ5 \
  | 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: e36009a94929c806e7be423fc5fdd4cf487ec466f2a1ae1a7438eb835495fe0f

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "3102ecd13d8a01bad3a1a13c91242acafcf03f1092bc23b7de5efca61555e759",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "cs.FL",
    "submitted_at": "2020-08-07T01:22:41Z",
    "title_canon_sha256": "f28b518d7ef89542aaac46f64ddbda4b210f63d9a1e8c249ba944e873b187aa6"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2008.04667",
    "kind": "arxiv",
    "version": 1
  }
}