Pith Number

pith:SDW2CLQT

pith:2025:SDW2CLQTDAFVYWEYINR5DTZGMO

not attested not anchored not stored refs pending

The challenge of hidden gifts in multi-agent reinforcement learning

Blake A. Richards, Dane Malenfant

Many state-of-the-art multi-agent reinforcement learning algorithms fail to learn collective rewards when success depends on hidden gifts from other agents' unobserved actions.

arxiv:2505.20579 v7 · 2025-05-26 · cs.LG · cs.AI · cs.MA

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Record completeness

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3 Author claim open · sign in to claim

4 Citations open

5 Replications 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

Several different state-of-the-art MARL algorithms, including MARL specific architectures, fail to learn how to obtain the collective reward in this simple task; decentralized actor-critic policy gradient agents can succeed when provided with information about their own action history, and a derived correction term for policy gradient agents reduces the variance in learning and helps them to converge to collective success more reliably.

C2weakest assumption

That the complete absence of any signal indicating other agents have dropped the key is the decisive factor causing MARL algorithms to fail at collective rewards, rather than other details of the grid-world dynamics, reward scaling, or training hyperparameters.

C3one line summary

In a grid-world task with one shared key and no feedback on others' drops, SOTA MARL algorithms fail at collective rewards but decentralized policy gradients with action history and a derived correction term succeed.

Formal links

2 machine-checked theorem links

Receipt and verification

First computed	2026-07-21T01:20:33.197163Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

90eda12e13180b5c58984363d1cf2663a7110f601102668e0c59e79efc69b71c

Aliases

arxiv: 2505.20579 · arxiv_version: 2505.20579v7 · doi: 10.48550/arxiv.2505.20579 · pith_short_12: SDW2CLQTDAFV · pith_short_16: SDW2CLQTDAFVYWEY · pith_short_8: SDW2CLQT

Agent API

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Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/SDW2CLQTDAFVYWEYINR5DTZGMO \
  | 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: 90eda12e13180b5c58984363d1cf2663a7110f601102668e0c59e79efc69b71c

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "229c863fbdf52527e57a767b1f868dbf5d00f7e980e47c981e4182dda0823a79",
    "cross_cats_sorted": [
      "cs.AI",
      "cs.MA"
    ],
    "license": "http://creativecommons.org/licenses/by/4.0/",
    "primary_cat": "cs.LG",
    "submitted_at": "2025-05-26T23:28:52Z",
    "title_canon_sha256": "607afafa99b172690fe27c68b4f874a939b6b7740991472d9ffc542eb52e7199"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2505.20579",
    "kind": "arxiv",
    "version": 7
  }
}