Summary: Definitional Trees
Sergio Antoy ?
Department of Computer Science
Portland State University
Portland, Oregon 97207­0751
Abstract. Rewriting is a computational paradigm that specifies the actions,
but not the control. We introduce a hierarchical structure representing, at a
high level of abstraction, a form of control. Its application solves a specific
problem arising in the design and implementation of inherently sequential,
lazy, functional programming languages based on rewriting. For example, we
show how to extend the expressive power of Log(F ) and how to improve the
efficiency of an implementation of BABEL. Our framework provides a notion
of degree of parallelism of an operation and shows that the elements of a
necessary set of redexes are related by an and­or relation. Both concepts find
application in parallel implementations of rewriting. In an environment in
which computations can be executed in parallel we are able to detect sequen­
tial computations in order to minimize overheads and/or optimize execution.
Conversely, we are able to detect when inherently sequential computations
can be executed in parallel without performing unnecessary rewrites.
1 Introduction and Motivations

Source: Antoy, Sergio - Department of Computer Science, Portland State University

Collections: Computer Technologies and Information Sciences