Abstract
In [10] it was shown that it is possible to describe the set of normal inhabitants of a given type τ, in the standard simple type system, using an infinitary extension of the concept of context-free grammar, which allows for an infinite number of non-terminal symbols as well as production rules. The set of normal inhabitants of τ corresponds then to the set of terms generated by this, possibly infinitary, grammar plus all terms obtained from those by η-reduction. In this paper we show that the set of normal inhabitants of a type τ can in fact be described using a standard (finite) context-free grammar, and more interestingly that normal inhabitants of types with the same structure are described by identical context-free grammars, up to renaming of symbols.
i.e. M is an inhabitant of τ
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Broda, S., Damas, L. (2001). A Context-Free Grammar Representation for Normal Inhabitants of Types in TAλ. In: Brazdil, P., Jorge, A. (eds) Progress in Artificial Intelligence. EPIA 2001. Lecture Notes in Computer Science(), vol 2258. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-45329-6_32
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DOI: https://doi.org/10.1007/3-540-45329-6_32
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