A static analysis for Bulk Synchronous Parallel ML to avoid parallel nesting

The BSMLlib library is a library for Bulk Synchronous Parallel (BSP) programming with the functional language Objective Caml. It is based on an extension of the λ-calculus by parallel operations on a data structure named parallel vector, which is given by intention. In order to have an execution that follows the BSP model, and to have a simple cost model, nesting of parallel vectors is not allowed. The novelty of this paper is a type system which prevents such nesting. This system is correct w.r.t. the dynamic semantics.