演算子不一致コントラスト学習による世界相対的な軌道整合性の評価
Operator-Mismatch Contrastive Learning for World-Relative Trajectory Coherence
世界モデルの軌道評価が『もっともらしさ』に偏り、実際に支配的な規則（演算子）の下での整合性を見落とす問題を定式化し、有効だが誤った演算子の軌道を負例とするコントラスト学習で世界相対的な整合性スコアを改善する手法を提案した。
著者: One Octadion, Firmansyah Sundana, Novanto Yudistira
分類: cs.LG
原文アブストラクト
World models are increasingly judged by how well they rank plausible futures, yet plausibility alone is the wrong target. The same scene can evolve under many latent rules, and a future that is smooth and physically valid under one rule can be incoherent under the rule actually in force. We formalize the resulting failure, operator-blindness, and show that it is systematically hidden by standard evaluation: a scorer can attain near-perfect generic ranking while separating current-world from other-world futures no better than chance. We introduce Operator-Mismatch Contrastive (OMC) learning, whose semantic hard negatives are valid-but-wrong-operator trajectories, and a matching protocol that measures world-relative coherence directly. On a controlled synthetic benchmark with in- and out-of-distribution operator parameters, across two trajectory-scoring backbones, and on feature-level external validation with CoPhy ballsCF, OMC raises operator-sensitive scoring far above a chance baseline that nonetheless achieves 0.99 generic top-1. We prove that the wrong-operator negative is necessary both for the protocol to detect the failure and for the objective to fix it, and position OMC as an auxiliary coherence signal (a trajectory-coherence scorer, not a generative model, planner, or control agent) that can be attached to existing world-model representations.