Pith Number

pith:57JXC3ME

pith:2010:57JXC3ME2F6JJNO5WXA2ZP7ZAT

not attested not anchored not stored refs pending

Computing the R of the QR factorization of tall and skinny matrices using MPI_Reduce

Julien Langou

arxiv:1002.4250 v1 · 2010-02-23 · math.NA · cs.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{57JXC3ME2F6JJNO5WXA2ZP7ZAT}

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	2026-06-03T23:06:34.033759Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

efd3716d84d17c94b5ddb5c1acbff904cb3e79124d33bcfc575791c08645d1da

Aliases

arxiv: 1002.4250 · arxiv_version: 1002.4250v1 · doi: 10.48550/arxiv.1002.4250 · pith_short_12: 57JXC3ME2F6J · pith_short_16: 57JXC3ME2F6JJNO5 · pith_short_8: 57JXC3ME

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/57JXC3ME2F6JJNO5WXA2ZP7ZAT \
  | 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: efd3716d84d17c94b5ddb5c1acbff904cb3e79124d33bcfc575791c08645d1da

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "7bb13758f62db6924504ff471c776c8601288b4b9488ff6dbaa8d7aa462f65b7",
    "cross_cats_sorted": [
      "cs.NA"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.NA",
    "submitted_at": "2010-02-23T06:13:42Z",
    "title_canon_sha256": "40cd3d6eb0c1cd1214bb9b474d18bf9883f3a67f89e86d1b1a682cd4186b6e9f"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1002.4250",
    "kind": "arxiv",
    "version": 1
  }
}