The paper gives a comprehensive presentation of a framework, embedded into
the simply typed higher-order logic, and aimed at providing a sound assistance
in formal reasoning about models of imperative programs with interleaved
computations. As a case study, a model of the Peterson's mutual exclusion
algorithm will be scrutinised in the course of the paper illustrating
applicability of the framework.Comment: 49 pages, to be published in Logical Methods in Computer Science;
  several rephrasings, a reference adde