Executing functional programs on a virtual tree of processors

A wide variety of computational models, including the lambda calculus, may be represented by a set of reduction rules which guide the (run-time) construction of a process tree. Even a single source of parallelism in an otherwise lazy evaluator may give rise to an exponential growth in the process tree, which must eventually overwhelm any finite architecture. We present a simple model for concurrently executing such process trees, which gives us a basis for matching the production of new tasks to the available resources. In addition, we present a generalised interpretation of a familiar topology suited to the support of large, perhaps irregular, virtual process trees on a much smaller physical network.