Message-passing software systems exhibit non-trivial forms of concurrency and distribution; they are expected to follow intended protocols among communicating services, but also to never “get stuck”. This intuitive requirement has been expressed by liveness properties such as progress or (dead)lock freedom and various type systems ensure these properties for concurrent processes. Unfortunately, very little is known about the precise relationship between these type systems and the classes of typed processes they induce.

This paper puts forward the first comparative study of different type systems for message-passing processes that guarantee deadlock freedom. We compare two classes of deadlock-free typed processes, here denoted $\mathcal{L}$ and $\mathcal{K}$. The class $\mathcal{L}$ stands out for its canonicity: it results from Curry-Howard interpretations of classical linear logic propositions as session types. The class $\mathcal{K}$, obtained by encoding session types into Kobayashi's linear types with usages, includes processes not typable in other type systems. We show that $\mathcal{L}$ is strictly included in $\mathcal{K}$, and identify the precise conditions under which they coincide. We also provide two type-preserving translations of processes in $\mathcal{K}$ into processes in $\mathcal{L}$.

消息传递软件系统表现出非平凡的并发和分发形式；他们应该遵循通信服务之间的预期协议，但也永远不会“卡住”。这种直观的要求已经通过诸如进度或（死）锁自由之类的活性属性来表达，并且各种类型系统确保了并发进程的这些属性。不幸的是，人们对这些类型系统与它们引发的类型化进程的类之间的确切关系知之甚少。

本文首次对保证死锁自由的消息传递过程的不同类型系统进行了比较研究。我们比较了两类无死锁的类型化进程，这里表示为$\mathcal{升}$ 和 $\mathcal{钾}$. 班上$\mathcal{升}$因其规范性而突出：它源于 Curry-Howard 将经典线性逻辑命题作为会话类型的解释。班上$\mathcal{钾}$，通过将会话类型编码为带有用法的小林线性类型而获得，包括在其他类型系统中不可类型化的进程。我们证明$\mathcal{升}$ 被严格包含在 $\mathcal{钾}$，并确定它们重合的精确条件。我们还提供两种类型保留的进程翻译$\mathcal{钾}$ 进入进程 $\mathcal{升}$.