Models change.
Proofs remain.

A regional bank approves a ¥5,000,000 small-business loan. The applicant's exact income is never disclosed to the bank's AI; Lemma proves only that income exceeds the policy threshold and that the applicant is not on any AML watchlist.

The same loan approval, but the approval document was edited after the AI signed it. Lemma detects the tampering before the document is presented to compliance.

A parts manufacturer ships a batch to an EU buyer. Lemma proves the production process conformed to the registered ESG/CBAM-compliant specification.

The same shipment, but a different AI inspection model was substituted between certification and shipment. Lemma detects the substitution via envelope signature mismatch.

An autonomous agent purchases an API service via x402 payment. Lemma proves the agent had delegation authority and that the payment receipt is genuine.

The same proof is submitted twice across two settlement steps — for example, a stuck retry loop in an agent pipeline. Lemma detects the duplicate proof_id and rejects the second submission.