Zena M. Ariola

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The mismatch between the operational semantics of the lambda calculus and the actual behavior of implementations is a major obstacle for compiler writers. They cannot explain the behavior of their evaluator in terms of source level syntax, and they cannot easily compare distinct implementations of different lazy strategies. In this paper we derive an(More)
The mismatch between the operational semantics of the lambda calculus and the actual behavior of implementations is a major obstacle for compiler writers. They cannot explain the behavior of their evaluator in terms of source level syntax, and they cannot easily compare distinct implementations of diierent lazy strategies. In this paper we derive an(More)
We present an equational framework for term graph rewriting with cycles. The usual notion of homomorphism is phrased in terms of the notion of bisimulation, which is well-known in process algebra and concurrency theory. Speciically, a homomorphism is a functional bisimulation. We prove that the bisimilarity class of a term graph, partially ordered by(More)
We precisely characterize a class of cyclic lambda-graphs, and then give a sound and complete axiomatization of the terms that represent a given graph. The equational axiom system is an extension of lambda calculus with the letrec construct. In contrast to current theories , which impose restrictions on where the rewriting can take place, our theory is very(More)
This paper is concerned with the study of-calculus with explicit recursion, namely of cyclic-graphs. The starting point is to treat a-graph as a system of recursion equations involving-terms, and to manipulate such systems in an unrestricted manner, using equational logic, just as is possible for rst-order term rewriting. Surprisingly, now the connuence(More)
This paper is concerned with the study of cyclic-graphs. The starting point is to treat a-graph as a system of recursion equations involving-terms, and to manipulate such systems in an unrestricted manner , using equational logic, just as is possible for rst-order term rewriting. Surprisingly, now the connuence property breaks down in an essential way.(More)
We introduce a framework for managing as a whole the space of a narrowing computation. The aim of our framework is to find a finite representation of an infinite narrowing space. This, in turn, allows us to replace an infinite enumeration of computed answers with an equivalent finite representation. We provide a semidecidable condition for this result. Our(More)