Pith Number

pith:UL5I747M

pith:2026:UL5I747MG5WKVSCFJTWH5AMHKL

not attested not anchored not stored refs pending

Characterizing the Expressivity of Local Attention in Transformers

Jiaoda Li, Ryan Cotterell

Local attention introduces a second temporal operator in transformers, strictly enlarging the class of recognizable regular languages beyond what global attention alone achieves.

arxiv:2605.00768 v2 · 2026-05-01 · cs.CL

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\pithnumber{UL5I747MG5WKVSCFJTWH5AMHKL}

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4 Citations open

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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.

Claims

C1strongest claim

We additionally prove that adding local attention introduces a second temporal operator, strictly enlarging the class of recognizable regular languages. Moreover, global and local attention are expressively complementary: neither subsumes the other, and combining them yields the richest fragment.

C2weakest assumption

The established correspondence between fixed-precision global-attention transformers and a single-past-operator fragment of linear temporal logic extends cleanly to local attention without additional restrictions that would limit the result to toy models rather than practical transformers.

C3one line summary

Local attention strictly enlarges the class of regular languages recognizable by fixed-precision transformers by adding a second past operator in linear temporal logic, with global and local attention being expressively complementary.

Receipt and verification

First computed	2026-05-20T01:05:15.036764Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

a2fa8ff3ec376caac8454cec7e818752f999cc78786ba053455d9c017312e7f0

Aliases

arxiv: 2605.00768 · arxiv_version: 2605.00768v2 · doi: 10.48550/arxiv.2605.00768 · pith_short_12: UL5I747MG5WK · pith_short_16: UL5I747MG5WKVSCF · pith_short_8: UL5I747M

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Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/UL5I747MG5WKVSCFJTWH5AMHKL \
  | 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: a2fa8ff3ec376caac8454cec7e818752f999cc78786ba053455d9c017312e7f0

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "4fc5a9bb3390f86196108506be9e6053a1f29b72ee0124d47334fe10e4e9de8d",
    "cross_cats_sorted": [],
    "license": "http://creativecommons.org/licenses/by/4.0/",
    "primary_cat": "cs.CL",
    "submitted_at": "2026-05-01T16:30:52Z",
    "title_canon_sha256": "fd25aa791c18a9d06471ccd3da2c9cb720ff875a1df8374eead3b427a5497ee1"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2605.00768",
    "kind": "arxiv",
    "version": 2
  }
}