This archive contains the Coq development described in the paper “Verifiable Semantic Difference Languages”[1]. It is composed of meta-theoritical definitions and proofs (coq/OracleLanguage.v, coq/ProgrammingLanguage.v, …) as well as an instantiation of those definitions on a toy imperative language (coq/Imp/). [1]: https://hal.inria.fr/hal-01653283/