{
  "public_id": "TA-2026-003",
  "version": "1.0",
  "released": "2026-11-07",
  "status": "published",
  "sample": false,
  "kind": "defect",
  "track": "game_theory",
  "title": "Balbus et al. (2019)",
  "headline": "Theorem 1(i) is false under the order assumptions as printed, and the appendix contains an independent function-space defect.",
  "work": {
    "authors": [
      "Łukasz Balbus",
      "Paweł Dziewulski",
      "Kevin Reffett",
      "Łukasz Woźny"
    ],
    "title": "A Qualitative Theory of Large Games with Strategic Complementarities",
    "venue": "Economic Theory",
    "year": 2019,
    "volume": "67",
    "pages": "497–523",
    "doi": "10.1007/s00199-017-1075-7"
  },
  "claims": [
    {
      "id": "c1",
      "label": "Theorem 1(i)",
      "kind": "theorem",
      "role": "main",
      "page": "503–504",
      "gist": "Under Assumption 1, greatest and least distributional equilibria exist.",
      "statement": "Under Assumption 1, there exists a greatest and a least distributional equilibrium of the game.",
      "conditions": [
        "compact perfect Hausdorff type space with a regular singleton-null probability measure",
        "weakly measurable complete-sublattice-valued feasible actions",
        "the printed partial-order condition that pair comparison implies action comparison",
        "quasisupermodularity, single-crossing differences and the stated Carathéodory condition"
      ],
      "quantifiers": "Every game admitted by the standing framework and Assumption 1.",
      "result": {
        "outcome": "defect_found",
        "candidate_status": "confirmed",
        "defect_class": "statement_false",
        "affects": "main_result",
        "depth": "deep_audit",
        "summary": "The literal one-way order condition admits a game satisfying Assumption 1 with no distributional equilibrium.",
        "witness": "Take types [0,1] with Lebesgue probability, actions {0,1}, a constant feasible-action set, and equality as the partial order on type-action pairs. Let p be the mass choosing action 1. Make action 1 uniquely optimal when p<1/2 and action 0 uniquely optimal when p≥1/2. Equality is permitted by the printed one-way order condition and makes the induced stochastic order equality, so the single-crossing condition is vacuous. Any equilibrium with p<1/2 would force p=1; any equilibrium with p≥1/2 would force p=0. Hence no distributional equilibrium exists.",
        "tested": "The exact assumption matrix, the induced stochastic order, strict best replies and the equilibrium contradiction were checked in a separate informed hostile validation. A strengthened four-action witness also defeats the possible rescue that greatest/least feasible distributions or chain completeness were intended as additional premises.",
        "not_claimed": [
          "The record does not claim that the authors' intended stronger order condition is false.",
          "Applications that independently impose a product or same-type action order are not claimed to fail.",
          "No downstream paper is claimed to be incorrect without checking its own assumptions."
        ],
        "repair": "local_repair_proposed",
        "repair_note": "A same-type fiber condition requiring action order to imply pair order excludes the counterexample and supplies a comparison used in the proof. The appendix chain-completeness argument still needs a separate valid justification."
      },
      "vor_check": {
        "level": "partial",
        "pages": "503–504",
        "detail": "The canonical source lock is partial because the historical decisive check used extracted final publisher text rather than a complete rendered-page verification. The theorem wording and order assumptions were rechecked on the publisher-hosted article during release preparation."
      },
      "checks": [
        {
          "kind": "ai_recheck",
          "date": "2026-10",
          "result": "confirms",
          "detail": "A separate informed hostile-validation session reconstructed the assumptions, tested rescue attempts and confirmed the exact counterexample.",
          "session": "informed"
        },
        {
          "kind": "private_human_confirmation",
          "date": "2026-10",
          "result": "confirms",
          "detail": "A qualifying human confirmation is recorded in the private research file. Its source and correspondence are not disclosed."
        }
      ],
      "novelty": null
    },
    {
      "id": "c2",
      "label": "Lemma A1 proof: function-space step",
      "kind": "lemma",
      "role": "auxiliary",
      "page": "519",
      "gist": "The proof treats M(X)-M(X), where M(X) contains bounded measurable isotone functions, as a Riesz subspace of C(X).",
      "statement": "In the proof of Lemma A1, M(X)-M(X) is asserted to be a Riesz subspace of the continuous functions C(X).",
      "conditions": [
        "X is a compact Hausdorff partially ordered space",
        "M(X) is defined as the bounded measurable isotone real-valued functions on X"
      ],
      "quantifiers": "The appendix argument is presented for the stated general class of compact ordered spaces and regular measures.",
      "result": {
        "outcome": "defect_found",
        "candidate_status": "confirmed",
        "defect_class": "missing_or_hidden_assumption",
        "affects": "lemma_or_proof_step",
        "depth": "deep_audit",
        "summary": "Measurability and isotonicity do not imply continuity, so the asserted inclusion in C(X) does not follow.",
        "witness": "Under the equality order, every bounded measurable function is isotone. Discontinuous indicator functions therefore belong to M(X), so M(X) and M(X)-M(X) need not be contained in C(X). The Stone-Weierstrass step cannot be justified from the displayed definition as written.",
        "tested": "The appendix definitions and the claimed Riesz-subspace step were traced in the historical audit and independently attacked in the hostile validation.",
        "not_claimed": [
          "This defect alone is not claimed to falsify the conclusion of Lemma A1.",
          "The record does not claim that no alternative proof of the relevant measure-order result exists.",
          "The record does not publish or rely on any private proposed correction."
        ],
        "repair": "local_repair_proposed",
        "repair_note": "The function class or the proof must be strengthened so that the functions used in the Stone-Weierstrass argument are continuous; a complete repair of the constrained-measure chain-completeness argument is not claimed here."
      },
      "vor_check": {
        "level": "partial",
        "pages": "519",
        "detail": "The canonical source lock is partial because the historical check used extracted final publisher text. The publisher-hosted article was rechecked during release preparation and still defines M(X) as measurable and bounded before asserting the subspace inclusion."
      },
      "checks": [
        {
          "kind": "ai_recheck",
          "date": "2026-10",
          "result": "confirms",
          "detail": "A separate informed hostile-validation session confirmed the mismatch between the displayed definition of M(X) and the continuity required by the proof.",
          "session": "informed"
        },
        {
          "kind": "private_human_confirmation",
          "date": "2026-10",
          "result": "confirms",
          "detail": "A qualifying human confirmation is recorded in the private research file. Its source and correspondence are not disclosed."
        }
      ],
      "novelty": null
    }
  ],
  "author_position": {
    "position": "not_disclosed",
    "summary": null
  },
  "correction": null,
  "evidence": {
    "package_doi": null,
    "package_sha256": null,
    "licence": "No public evidence package released.",
    "files": []
  },
  "history": [
    {
      "date": "2026-10",
      "type": "audit",
      "label": "Theorem-level counterexample and appendix defect identified and separately rechecked"
    },
    {
      "date": "2026-10",
      "type": "source",
      "label": "Published-source text checked; canonical VOR level remains partial"
    },
    {
      "date": "2026-11-07",
      "type": "release",
      "label": "Record version 1.0 released"
    }
  ],
  "challenges": [],
  "changelog": [
    {
      "version": "1.0",
      "date": "2026-11-07",
      "change": "First release."
    }
  ],
  "statements": {
    "ai_use": "AI systems were used for discovery and separate hostile rechecking. Confirmation also includes a qualifying human check recorded privately. Private correspondence is not disclosed, and AI agreement is not treated as human verification."
  }
}
