Pith Number

pith:E42JQBMP

pith:2013:E42JQBMPPEIQVEO6K5OIBU7CAB

not attested not anchored not stored refs pending

Efficient methods for computing observation impact in 4D-Var data assimilation

Adrian Sandu, Alexandru Cioaca, Eric de Sturler

arxiv:1305.5796 v2 · 2013-05-24 · cs.CE · math.NA

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{E42JQBMPPEIQVEO6K5OIBU7CAB}

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	2026-05-18T03:18:05.907388Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

273498058f79110a91de575c80d3e200720da5d0d0e7867cf7f847d2d8c3cdbd

Aliases

arxiv: 1305.5796 · arxiv_version: 1305.5796v2 · doi: 10.48550/arxiv.1305.5796 · pith_short_12: E42JQBMPPEIQ · pith_short_16: E42JQBMPPEIQVEO6 · pith_short_8: E42JQBMP

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/E42JQBMPPEIQVEO6K5OIBU7CAB \
  | 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: 273498058f79110a91de575c80d3e200720da5d0d0e7867cf7f847d2d8c3cdbd

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "0148115c326a5509a41b375c980448b8f6625eb62fa1956bb14c55b755725c39",
    "cross_cats_sorted": [
      "math.NA"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "cs.CE",
    "submitted_at": "2013-05-24T17:00:00Z",
    "title_canon_sha256": "4c3cbf05570cdc239420b29fc530e5370ab119e137c14edcbb02acfb7f20d45e"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1305.5796",
    "kind": "arxiv",
    "version": 2
  }
}