Pith Number

pith:CQGK3BLQ

pith:2019:CQGK3BLQTPAIBSYBZ4FOWXAY3B

not attested not anchored not stored refs pending

On the ${\Ext}^2$-problem for Hilbert spaces

F\'elix Cabello S\'anchez, Jes\'us M.F. Castillo, Ricardo Garc\'ia, Valentin Ferenczi, Willian H. G. Corr\^ea

arxiv:1908.06529 v2 · 2019-08-18 · math.FA

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{CQGK3BLQTPAIBSYBZ4FOWXAY3B}

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	2026-07-05T00:29:20.461576Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

140cad85709bc080cb01cf0aeb5c18d8462eb30e7586c0665a3ab9ae807911a1

Aliases

arxiv: 1908.06529 · arxiv_version: 1908.06529v2 · doi: 10.48550/arxiv.1908.06529 · pith_short_12: CQGK3BLQTPAI · pith_short_16: CQGK3BLQTPAIBSYB · pith_short_8: CQGK3BLQ

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/CQGK3BLQTPAIBSYBZ4FOWXAY3B \
  | 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: 140cad85709bc080cb01cf0aeb5c18d8462eb30e7586c0665a3ab9ae807911a1

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "1f0e932f9d4b1519b9dd93f5784cbc16eb0e4db48ef2d89b8b76dd4a01b35ac3",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "math.FA",
    "submitted_at": "2019-08-18T22:51:01Z",
    "title_canon_sha256": "37c87482541d1ed485776651824626db210fc51f06b4932caff4ab653b600760"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1908.06529",
    "kind": "arxiv",
    "version": 2
  }
}