A tier-based typed programming language characterizing Feasible Functionals

The class of Basic Feasible Functionals BFF$_2$ is the type-2 counterpart FP type-1 functions computable in polynomial time. Several characterizations have been suggested literature, but none these present a programming language with type system guaranteeing this complexity bound. We give characterization based on an imperative oracle calls using tier-based whose inference decidable. Such should make it possible to link higher-order theory. low (cubic size program) algorithm contrasts intractability aforementioned methods and does not overly constrain expressive power language.