OOlong: a concurrent object calculus for extensibility and reuse

We present OOlong, an object calculus with interface inheritance, structured concurrency and locks. The goal of the calculus is extensibility and reuse. The semantics are therefore available in a version for L A T E X typesetting (written in Ott), a mechanised version for doing rigorous proofs in Coq, and a prototype interpreter (written in OCaml) for typechecking an running OOlong programs.