AEMB: A Deterministic Cross-Language Verification Benchmark for Event-Margin Protocols

Event-margin protocols span financial accounting, venue evidence, smart contracts, services, user interfaces, and operational recovery. Unit tests within one implementation cannot establish that a Python model, Solidity contracts, TypeScript services, and venue adapters preserve the same meaning under the same event sequence. This paper introduces the Axient Event-Margin Protocol Verification Benchmark (AEMB), a deterministic and implementation-neutral conformance benchmark for that cross-layer problem. AEMB v0.1.0 contains 38 source-generated scenarios anchored to an immutable reference implementation: eight financial vertical slices, fifteen venue-adapter boundary cases, and fifteen operational or fault rehearsals. Each case declares preconditions, typed actions, expected transitions, balance conventions, outcome hashes, negative controls, and invariant mappings. Conformance is conjunctive: a mandatory schema, transition, hash, safety-boundary, or reproducibility failure cannot be offset by success elsewhere. Python, Node.js, and Go canonicalizers agree on 11,400 recursive key-order comparisons with zero failures; a strict offline Draft 2020-12 schema accepts all canonical cases and rejects twelve malformed controls; and 190 one-field complete-case mutations all change case identity. The benchmark separates outcome, case, collection, dataset, and package identities and defines correction, extension, licensing, and archival rules. AEMB is synthetic and deterministic. It contains no raw third-party venue data, user identifiers, external writes, or production asset movement, and it does not certify production safety or live venue compatibility. Its contribution is a portable benchmark object, exact cross-language evidence, and a governance protocol for future cases derived from audits, incidents, and empirical traces.