Pith Number

pith:ZXHVOWKM

pith:2015:ZXHVOWKM3KDA27RBALTHPITHEX

not attested not anchored not stored refs pending

NP-Hardness and Inapproximability of Sparse PCA

Malik Magdon-Ismail

arxiv:1502.05675 v2 · 2015-02-19 · cs.LG · cs.CC · cs.DS · math.CO · stat.ML

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{ZXHVOWKM3KDA27RBALTHPITHEX}

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	2026-05-18T02:26:44.979203Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

cdcf57594cda860d7e2102e677a26725fca1e10f95817fb57d8a0e3a3412280e

Aliases

arxiv: 1502.05675 · arxiv_version: 1502.05675v2 · doi: 10.48550/arxiv.1502.05675 · pith_short_12: ZXHVOWKM3KDA · pith_short_16: ZXHVOWKM3KDA27RB · pith_short_8: ZXHVOWKM

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/ZXHVOWKM3KDA27RBALTHPITHEX \
  | 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: cdcf57594cda860d7e2102e677a26725fca1e10f95817fb57d8a0e3a3412280e

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "057f70e802bc4d3471369634f2399adddc7bf480770ba2e8c2925dd43faeea86",
    "cross_cats_sorted": [
      "cs.CC",
      "cs.DS",
      "math.CO",
      "stat.ML"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "cs.LG",
    "submitted_at": "2015-02-19T19:30:46Z",
    "title_canon_sha256": "7e0260a5d63f470b451dae88569dee7249da3b6dbd516e6c0bfe53ac6d2f3147"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1502.05675",
    "kind": "arxiv",
    "version": 2
  }
}