Pith Number

pith:L4XQ3ZQS

pith:2026:L4XQ3ZQSL4V6SX6CQX3GKBIWLG

not attested not anchored not stored refs pending

The Optimal Knight Exchange Puzzle is NP-Hard

Henry Siegel

arxiv:2606.29153 v1 · 2026-06-28 · cs.DM · cs.CC

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{L4XQ3ZQSL4V6SX6CQX3GKBIWLG}

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	2026-06-30T01:17:54.800851Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

5f2f0de6125f2be95fc285f6650516598f7eb191e74f2d247cb8e515985c67b1

Aliases

arxiv: 2606.29153 · arxiv_version: 2606.29153v1 · doi: 10.48550/arxiv.2606.29153 · pith_short_12: L4XQ3ZQSL4V6 · pith_short_16: L4XQ3ZQSL4V6SX6C · pith_short_8: L4XQ3ZQS

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/L4XQ3ZQSL4V6SX6CQX3GKBIWLG \
  | 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: 5f2f0de6125f2be95fc285f6650516598f7eb191e74f2d247cb8e515985c67b1

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "dc52b19517cf54832d379b6ba203b0043c8488f0892fa145c4c66fe630da139a",
    "cross_cats_sorted": [
      "cs.CC"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "cs.DM",
    "submitted_at": "2026-06-28T02:22:16Z",
    "title_canon_sha256": "cf82a762cd9d6d00b9b27e61251d4fe4467707668721d416a09b168642e236ba"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2606.29153",
    "kind": "arxiv",
    "version": 1
  }
}