🤖 AI Summary
This paper addresses the challenge of modularly reasoning about error probability bounds in higher-order concurrent probabilistic programs. To this end, it introduces Coneris—the first separation logic supporting such reasoning. Methodologically, it pioneers the concept of “randomized logical atomicity,” extending linearizability to probabilistic semantics by introducing pre-sampled traces and a probabilistic update modality to capture probabilistic state evolution at linearization points. Built upon the Rocq and Iris frameworks, Coneris integrates higher-order separation logic, probabilistic semantic modeling, and formal verification techniques. Its contributions are threefold: (1) the first modular verification framework for error probability bounds of higher-order concurrent probabilistic modules; (2) a fully mechanized metatheory and validation across multiple case studies, including large-scale systems; and (3) rigorous guarantees of correctness and composability for derived error upper bounds.
📝 Abstract
We present Coneris, the first higher-order concurrent separation logic for reasoning about error probability bounds of higher-order concurrent probabilistic programs with higher-order state. To support modular reasoning about concurrent (non-probabilistic) program modules, state-of-the-art program logics internalize the classic notion of linearizability within the logic through the concept of logical atomicity. Coneris extends this idea to probabilistic concurrent program modules. Thus Coneris supports modular reasoning about probabilistic concurrent modules by capturing a novel notion of randomized logical atomicity within the logic. To do so, Coneris utilizes presampling tapes and a novel probabilistic update modality to describe how state is changed probabilistically at linearization points. We demonstrate this approach by means of smaller synthetic examples and larger case studies. All of the presented results, including the meta-theory, have been mechanized in the Rocq proof assistant and the Iris separation logic framework