Pith Number

pith:CYE2CB66

pith:2001:CYE2CB6642EXNLQ5C4WDK27H7P

not attested not anchored not stored refs pending

Obstruction Theory in Model Categories

Daniel C. Isaksen, J. Daniel Christensen, William G. Dwyer

arxiv:math/0109170 v3 · 2001-09-23 · math.AT · math.CT

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

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{CYE2CB6642EXNLQ5C4WDK27H7P}

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	2026-05-18T00:40:35.300000Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

1609a107dee68976ae1d172c356be7fbcfdac27c1d0f08393c9974b493a1fd46

Aliases

arxiv: math/0109170 · arxiv_version: math/0109170v3 · doi: 10.48550/arxiv.math/0109170 · pith_short_12: CYE2CB6642EX · pith_short_16: CYE2CB6642EXNLQ5 · pith_short_8: CYE2CB66

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/CYE2CB6642EXNLQ5C4WDK27H7P \
  | 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: 1609a107dee68976ae1d172c356be7fbcfdac27c1d0f08393c9974b493a1fd46

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "02a04b0edb968b4aab85dd8bdad67429e224f6eb1e6e13519c44fb651d13295c",
    "cross_cats_sorted": [
      "math.CT"
    ],
    "license": "",
    "primary_cat": "math.AT",
    "submitted_at": "2001-09-23T00:41:53Z",
    "title_canon_sha256": "803a2dda8df6485adcd20cc733bebadc7a96bd2bd7bce593356ad267b0ce4ec8"
  },
  "schema_version": "1.0",
  "source": {
    "id": "math/0109170",
    "kind": "arxiv",
    "version": 3
  }
}