Pith Number

pith:GXC4VRPP

pith:2002:GXC4VRPPM6LVJ2J2GLQGTALCV6

not attested not anchored not stored refs pending

Tetris is Hard, Even to Approximate

David Liben-Nowell, Erik D. Demaine, Susan Hohenberger

arxiv:cs/0210020 v1 · 2002-10-21 · cs.CC · cs.CG · cs.DM

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{GXC4VRPPM6LVJ2J2GLQGTALCV6}

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.

Cited by

1 paper in Pith

LaserTank is NP-complete

Receipt and verification

First computed	2026-07-04T14:24:21.611322Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

35c5cac5ef679754e93a32e0698162afaadc44e27b97f0ebc018c09a958a9eec

Aliases

arxiv: cs/0210020 · arxiv_version: cs/0210020v1 · doi: 10.48550/arxiv.cs/0210020 · pith_short_12: GXC4VRPPM6LV · pith_short_16: GXC4VRPPM6LVJ2J2 · pith_short_8: GXC4VRPP

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/GXC4VRPPM6LVJ2J2GLQGTALCV6 \
  | 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: 35c5cac5ef679754e93a32e0698162afaadc44e27b97f0ebc018c09a958a9eec

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "645b003bf42be1631fde1ded97d5b10122cc6b1e384338f73d4d5072d6dafa21",
    "cross_cats_sorted": [
      "cs.CG",
      "cs.DM"
    ],
    "license": "",
    "primary_cat": "cs.CC",
    "submitted_at": "2002-10-21T18:32:39Z",
    "title_canon_sha256": "a6f7cf5c97e6f9ed557aaf9ace0fb18ee766d8b43ca45fa5d84f990a38998560"
  },
  "schema_version": "1.0",
  "source": {
    "id": "cs/0210020",
    "kind": "arxiv",
    "version": 1
  }
}