Thread algebra for strategic interleaving

We take a thread as the behavior of a sequential deterministic program under execution and multi-threading as the form of concurrency provided by contemporary programming languages such as Java and C#. We outline an algebraic theory about threads and multi-threading. In the case of multi-threading, some deterministic interleaving strategy determines how threads are interleaved. Interleaving operators for a number of plausible interleaving strategies are specified in a simple and concise way. By that, we show that it is essentially open-ended what counts as an interleaving strategy. We use deadlock freedom as an example to show that there are properties of multi-threaded programs that depend on the interleaving strategy used.