Incompleteness of AI Safety Verification via Kolmogorov Complexity

arXiv cs.AI / 4/7/2026

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Key Points

  • The paper argues that the difficulty of verifying AI safety and policy compliance is not only due to computational limits or model expressiveness, but also due to intrinsic information-theoretic barriers.
  • It formalizes policy compliance as a verification problem over encoded system behaviors and analyzes the limits using Kolmogorov complexity.
  • The authors prove an incompleteness theorem: for any fixed sound computably enumerable verifier, there is a complexity threshold beyond which true policy-compliant instances cannot be certified.
  • This implies that no finite formal verifier can guarantee certification for all policy-compliant instances with arbitrarily high complexity, even ignoring resource constraints.
  • The work motivates “proof-carrying” approaches that can provide instance-level correctness guarantees rather than relying solely on finite, fixed verifiers.

Abstract

Ensuring that artificial intelligence (AI) systems satisfy formal safety and policy constraints is a central challenge in safety-critical domains. While limitations of verification are often attributed to combinatorial complexity and model expressiveness, we show that they arise from intrinsic information-theoretic limits. We formalize policy compliance as a verification problem over encoded system behaviors and analyze it using Kolmogorov complexity. We prove an incompleteness result: for any fixed sound computably enumerable verifier, there exists a threshold beyond which true policy-compliant instances cannot be certified once their complexity exceeds that threshold. Consequently, no finite formal verifier can certify all policy-compliant instances of arbitrarily high complexity. This reveals a fundamental limitation of AI safety verification independent of computational resources, and motivates proof-carrying approaches that provide instance-level correctness guarantees.