Pith Number

pith:Y6YCGZV3

pith:2000:Y6YCGZV3KXUTYSWIF5WEVBICGW

not attested not anchored not stored refs pending

Negative Group Velocity

Kirk T. McDonald

arxiv:physics/0008013 v4 · 2000-08-05 · physics.optics

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{Y6YCGZV3KXUTYSWIF5WEVBICGW}

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	2026-07-04T16:22:13.709339Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

c7b02366bb55e93c4ac82f6c4a850235a947a943d2c6415f69eecd5c24173a72

Aliases

arxiv: physics/0008013 · arxiv_version: physics/0008013v4 · doi: 10.48550/arxiv.physics/0008013 · pith_short_12: Y6YCGZV3KXUT · pith_short_16: Y6YCGZV3KXUTYSWI · pith_short_8: Y6YCGZV3

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/Y6YCGZV3KXUTYSWIF5WEVBICGW \
  | 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: c7b02366bb55e93c4ac82f6c4a850235a947a943d2c6415f69eecd5c24173a72

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "ef343457f9d7b37ce195b9333b63b7a11dd3d1c2893b3430b7826c8faecb2cab",
    "cross_cats_sorted": [],
    "license": "",
    "primary_cat": "physics.optics",
    "submitted_at": "2000-08-05T20:27:23Z",
    "title_canon_sha256": "d5416f889eced3b13254bc7cae5cf12a9beea0421c15a530b8438ee4c3bd3f17"
  },
  "schema_version": "1.0",
  "source": {
    "id": "physics/0008013",
    "kind": "arxiv",
    "version": 4
  }
}